The Anvil Platform enables paperwork automation in a data-centric world

Anvil

anvil

How to build a web UI with Python Anvil lets you build your app’s front-end entirely in Python - no HTML, CSS or Javascript required. You can build your UI by dragging and dropping components in Anvil’s visual designer or by adding components using Python code: Let’s look at how you can use the to create a user interface by turning this app into a “hello world” app that says hello to your users. Anvil editor In the middle of the Anvil IDE is the which is split into the Design View and the Code View. On the right of the Anvil editor you will find the . Form Editor Toolbox You can drag and drop components, like , from the toolbox to build your user interface. This hello world app will also need a for users to enter their name: Labels TextBox To configure components, you can edit their on the right hand side in the . This includes both the information the component displays and its styling: properties Properties Panel Every component is a Python object, so you can also set the component’s properties in the Code View: Form Editor’s All components have they can raise. For example, when a user of your app clicks a component it raises a click event. We can create a Python method in the Code View to be called when this happens. In your Button’s click method, you can call Anvil’s function to display an alert that says hello to your users: events Button alert Now you can click run to test your app and it’s interface. Your users can now enter their name and clicking the button displays the alert: say hi Using the drag and drop designer isn’t your only option for building user interfaces in Anvil. You can also create and add components to your user interface directly in code: Anvil comes with all the - buttons, text boxes, drop-downs, tables, and so on. And if that’s not enough, you can create your own and share them with other applications. usual UI components custom components To learn more about creating user interfaces with Anvil, why not get started with our 10 minute Feedback Form Tutorial? >>> Get started Build your own app with Anvil If you’re new here, welcome! is a platform for building full-stack web apps with nothing but Python. No need to wrestle with JS, HTML, CSS, Python, SQL and all their frameworks – just . Anvil build it all in Python >>> Try Anvil

How to Make a Web App User Interface with Python

Cómo hacer una interfaz de usuario de una aplicación web con Python

Hey there, fellow Android developers! 👋 Are you tired of the hassle that comes with managing assisted injection in your modular app? Well, buckle up because I've got some exciting news for you! 🚀 Introducing Anvil Utils - a game-changing library that will make your life easier when working with Dagger and Anvil in multi-module projects. The Struggle Is Real Picture this: you have a beautifully architected modular app with api and implementation modules per feature. Everything is going smoothly until you encounter a situation where your feature contains a factory for an entity and want to expose it in an api, and you need to make this factory available within the Dagger graph. 😰 Let's walk through the ways to do that. Bare Dagger Approach For instance, you have such public API for your feature module: interface MyClass {
	interface Factory {
	    fun create(param1: String, param2: Int): MyClass
	}
} Traditionally, you'd have to manually create an @AssistedFactory in the implementation module, inherit from the public interface in the API module, and write a Dagger module which binds assisted factory to it's public interface. Also, you would need to maintain both factory interfaces - public one and implementation one. Here's an example: class DefaultMyClass @AssistedInject constructor(
    @Assisted param1: String,
    @Assisted param2: Int
) : MyClass {
	@AssistedFactory
	interface Factory: MyClass.Factory {
		override fun create(param1: String, param2: Int): DefaultMyClass
	}
}

@Module
interface MyClassFactoryBindingModule {
	@Binds
	fun bindFactory(impl: DefaultMyClass.Factory): MyClass.Factory
} Seems like a lot of work, doesn't it? Let's make it easier to maintain step by step Introducing Anvil Anvil is a Kotlin compiler plugin which helps to drastically reduce the boilerplate needed to use Dagger 2 in your application. Also, if properly configured, it can improve build times in your application by removing the requirement to run Dagger 2 annotation processor in your feature modules. I will not dive deep into what Anvil is and why you should consider using it. That's a topic for another day. Please read through the Anvil readme here to get what it is about. https://github.com/square/anvil Thanks to Anvil, you can get rid of the binding module using @ContributesBinding: class DefaultMyClass @AssistedInject constructor(
    @Assisted param1: String,
    @Assisted param2: Int
) : MyClass {
	@ContributesBinding(AppGraph::class, MyClass.Factory::class)
	@AssistedFactory
	interface Factory: MyClass.Factory {
		override fun create(param1: String, param2: Int): DefaultMyClass
	}
} Anvil will generate corresponding module which will bind DefaultMyClass.Factory to MyClass.Factory for you. This lowers the amount of boilerplate, but it's still there! You have to manually keep public factory interface and implementation interface aligned with the constructor! Can we go further and reduce the amount of work needed to support this use case? Sure! @ContributesAssistedFactory to the Rescue! Fear not, my friend! With Anvil Utils, you can say goodbye to the manual labor of creating assisted factories. The @ContributesAssistedFactory annotation is here to save the day! 🦸‍♂️ This powerful annotation automatically generates assisted factories for your annotated classes and contributes them to the specified scope as bindings of the provided factory type. It's like having a personal assistant that takes care of all the heavy lifting for you! You now can remove the @AssistedFactory interface completely and annotate the DefaultMyClass with @ContributesAssistedFactory: @ContributesAssistedFactory(AppGraph::class, MyClass.Factory::class)
class DefaultMyClass @AssistedInject constructor(
    @Assisted param1: String,
    @Assisted param2: Int
) : MyClass And voila! Anvil Utils will generate the necessary assisted factory for you, without breaking a sweat. 😎 In the Wild Example To demonstrate the power of this library, I've made a huge pull request to beautiful open-source project - companion app for the Flipper - Tamagochi for hackers. Please, take a look if you're interested: https://github.com/flipperdevices/Flipper-Android-App/pull/79 Embrace the Power of Anvil Utils So, what are you waiting for? Give Anvil Utils a try in your next modular Android project and experience the joy of hassle-free assisted injection. Your codebase will thank you, and your fellow developers will be in awe of your newfound superpowers! 💪 Happy coding, and may the power of Anvil Utils be with you! 🚀 P.S. Don't hesitate to open feature requests - I'm eager to improve the library and add more features. Hey there, fellow Android developers! 👋 Are you tired of the hassle that comes with managing assisted injection in your modular app? Well, buckle up because I've got some exciting news for you! 🚀 Introducing Anvil Utils - a game-changing library that will make your life easier when working with Dagger and Anvil in multi-module projects. Anvil Utils Anvil Utils Anvil The Struggle Is Real Picture this: you have a beautifully architected modular app with api and implementation modules per feature. Everything is going smoothly until you encounter a situation where your feature contains a factory for an entity and want to expose it in an api , and you need to make this factory available within the Dagger graph. 😰 api implementation api Let's walk through the ways to do that. Bare Dagger Approach For instance, you have such public API for your feature module: interface MyClass {
	interface Factory {
	    fun create(param1: String, param2: Int): MyClass
	}
} interface MyClass {
	interface Factory {
	    fun create(param1: String, param2: Int): MyClass
	}
} Traditionally, you'd have to manually create an @AssistedFactory in the implementation module, inherit from the public interface in the API module, and write a Dagger module which binds assisted factory to it's public interface. Also, you would need to maintain both factory interfaces - public one and implementation one. Here's an example: @AssistedFactory class DefaultMyClass @AssistedInject constructor(
    @Assisted param1: String,
    @Assisted param2: Int
) : MyClass {
	@AssistedFactory
	interface Factory: MyClass.Factory {
		override fun create(param1: String, param2: Int): DefaultMyClass
	}
}

@Module
interface MyClassFactoryBindingModule {
	@Binds
	fun bindFactory(impl: DefaultMyClass.Factory): MyClass.Factory
} class DefaultMyClass @AssistedInject constructor(
    @Assisted param1: String,
    @Assisted param2: Int
) : MyClass {
	@AssistedFactory
	interface Factory: MyClass.Factory {
		override fun create(param1: String, param2: Int): DefaultMyClass
	}
}

@Module
interface MyClassFactoryBindingModule {
	@Binds
	fun bindFactory(impl: DefaultMyClass.Factory): MyClass.Factory
} Seems like a lot of work, doesn't it? Let's make it easier to maintain step by step Introducing Anvil Anvil is a Kotlin compiler plugin which helps to drastically reduce the boilerplate needed to use Dagger 2 in your application. Anvil Also, if properly configured, it can improve build times in your application by removing the requirement to run Dagger 2 annotation processor in your feature modules. I will not dive deep into what Anvil is and why you should consider using it. That's a topic for another day. Please read through the Anvil readme here to get what it is about. https://github.com/square/anvil https://github.com/square/anvil Thanks to Anvil, you can get rid of the binding module using @ContributesBinding : @ContributesBinding class DefaultMyClass @AssistedInject constructor(
    @Assisted param1: String,
    @Assisted param2: Int
) : MyClass {
	@ContributesBinding(AppGraph::class, MyClass.Factory::class)
	@AssistedFactory
	interface Factory: MyClass.Factory {
		override fun create(param1: String, param2: Int): DefaultMyClass
	}
} class DefaultMyClass @AssistedInject constructor(
    @Assisted param1: String,
    @Assisted param2: Int
) : MyClass {
	@ContributesBinding(AppGraph::class, MyClass.Factory::class)
	@AssistedFactory
	interface Factory: MyClass.Factory {
		override fun create(param1: String, param2: Int): DefaultMyClass
	}
} Anvil will generate corresponding module which will bind DefaultMyClass.Factory to MyClass.Factory for you. Anvil DefaultMyClass.Factory MyClass.Factory This lowers the amount of boilerplate, but it's still there! You have to manually keep public factory interface and implementation interface aligned with the constructor! Can we go further and reduce the amount of work needed to support this use case? Sure! @ContributesAssistedFactory to the Rescue! Fear not, my friend! With Anvil Utils , you can say goodbye to the manual labor of creating assisted factories. The @ContributesAssistedFactory annotation is here to save the day! 🦸‍♂️ Anvil Utils Anvil Utils @ContributesAssistedFactory This powerful annotation automatically generates assisted factories for your annotated classes and contributes them to the specified scope as bindings of the provided factory type. It's like having a personal assistant that takes care of all the heavy lifting for you! You now can remove the @AssistedFactory interface completely and annotate the DefaultMyClass with @ContributesAssistedFactory : @AssistedFactory DefaultMyClass @ContributesAssistedFactory @ContributesAssistedFactory(AppGraph::class, MyClass.Factory::class)
class DefaultMyClass @AssistedInject constructor(
    @Assisted param1: String,
    @Assisted param2: Int
) : MyClass @ContributesAssistedFactory(AppGraph::class, MyClass.Factory::class)
class DefaultMyClass @AssistedInject constructor(
    @Assisted param1: String,
    @Assisted param2: Int
) : MyClass And voila! Anvil Utils will generate the necessary assisted factory for you, without breaking a sweat. 😎 Anvil Utils Anvil Utils In the Wild Example To demonstrate the power of this library, I've made a huge pull request to beautiful open-source project - companion app for the Flipper - Tamagochi for hackers. Please, take a look if you're interested: https://github.com/flipperdevices/Flipper-Android-App/pull/79 https://github.com/flipperdevices/Flipper-Android-App/pull/79 Embrace the Power of Anvil Utils So, what are you waiting for? Give Anvil Utils a try in your next modular Android project and experience the joy of hassle-free assisted injection. Your codebase will thank you, and your fellow developers will be in awe of your newfound superpowers! 💪 Anvil Utils Anvil Utils Happy coding, and may the power of Anvil Utils be with you! 🚀 Anvil Utils Anvil Utils P.S. Don't hesitate to open feature requests - I'm eager to improve the library and add more features. P.S.

Effortless Assisted Injection in Multi-Module Android Projects: Introducing Anvil Utils

Prague, Czech Republic, Nov 28, 2023, BTCWire Wake is a Python-based Solidity development and testing framework with built-in vulnerability detectors. It was used in audits by Ackee Blockchain and is now being open-sourced and free to use for everyone. Security experts are on high alert, as history shows that hack risks increase as market activity rises. Open-source tooling like Wake empowers application builders to conduct swift and thorough checks for code vulnerabilities. Battlefield-proven audit tool goes open-source , a team of smart contract auditors and creators of community tools, introduces Wake, a Python-based development and testing framework for Solidity and cross-chain fuzzing with a proven track record of stopping bugs. Ackee Blockchain Wake’s features include a development and testing framework, a fuzzer, vulnerability detectors, and printers. Wake was previously used in smart contract audits for , , and and helped the auditors find critical, high, and medium bugs. The firm has announced it will make the tool open-source to contribute to a safer blockchain space. performed by Ackee Blockchain IPOR Axelar Solady Security experts on alert as market activity rises As DeFi activity rises, hackers see more lucrative targets and grow emboldened. In bull markets, projects often rush to ship product updates, creating a high demand for experienced smart contract auditor services. In the peak of the 2021 bull market, projects were typically quoted three month+ audit wait times by reputable firms. They then face a difficult decision to delay launches amid frenzied “land grabs” or launch with hastily conducted audits, increasing security risks. After a week when crypto funds saw their highest inflows since the 2021 bull market and DeFi volumes rose by approximately 50%, security experts are on higher alert. Wake’s release is timely - it allows application developers to expertly test the smart contracts of DEXs or any protocol that plugs into their service or upon which they are reliant. Designed to generate fewer false positives and reduce manual audit time On top of being the testing framework, Wake allows users to run static analysis. It has a set of ready-to-use high-precision vulnerability and code quality detectors and ready-to-use printers for extracting and pretty-printing useful information such as smart contract control flow and inheritance graphs. “A common problem of static analysis tools is a high false-positives ratio requiring extra manual investigation time. Our philosophy is to include only the most precise detectors and reduce all noise that creates extra overhead,” - Josef Gattermayer, CEO and co-founder of Ackee Blockchain. Wake underwent performance , namely Hardhat, Brownie, and Ape, on three different development chains – Anvil, Ganache, and Hardhat. Wake proved to be the fastest Python framework. testing with other frameworks The new release of Wake allows the customization of detectors and printers. It also allows third parties to create and implement their custom printers and detectors. The newest version also introduced Github action for automatically executing detectors in a pipeline. “The low false-positive rate, fastest industry test execution, and ready-made GitHub action make Wake an ideal candidate for CI/CD integration in every project” - Josef Gattermayer, CEO and co-founder of Ackee Blockchain. Wake powers , a popular Visual Studio Code Solidity extension that does syntax highlighting and detections from Wake vulnerability and code quality detectors and provides instant feedback to the developers using the extension access to all references of a symbol across the whole project. Tools for Solidity About Wake Wake is a Python-based development and testing framework for Solidity and cross-chain fuzzing with a proven track record of stopping bugs created by , which became possible thanks to a grant Ackee Blockchain received from Coinbase in 2022. Ackee Blockchain To learn more, please visit . getwake.io | | Website Twitter Telegram About Ackee Blockchain Ackee Blockchain is a team of security researchers auditing top-tier protocols: Safe, 1inch, Axelar, LayerZero, Trader Joe, or CoW Protocol. Ackee Blockchain is backed by the largest VC fund focused on blockchain and DeFi in Europe, RockawayX, and received grants from the Ethereum Foundation, Tezos Foundation, Coinbase, and Solana Foundation. Ackee Blockchain’s mission is to build a stronger blockchain community by sharing knowledge: the team runs a free certification course , and teaches at the Czech Technical University in Prague. This mission is also fulfilled in initiatives such as the ERC-7512 draft, the development of the Wake toolkit, and the development of the open-source fuzzer for Solana. School of Solidity School of Solana | Website Twitter For media inquiries or further information, please contact marketing@ackeeblockchain.com

Wake Testing Tool for Solidity is Now Open Sourced for the Blockchain Dev Community

সলিডিটির জন্য ওয়েক টেস্টিং টুল এখন ব্লকচেইন দেব সম্প্রদায়ের জন্য ওপেন সোর্স

Das Wake Testing Tool für Solidity ist jetzt Open Source für die Blockchain Dev Community

La herramienta de prueba Wake para Solidity ahora es de código abierto para la comunidad de desarrolladores de Blockchain

L'outil de test Wake pour Solidity est désormais open source pour la communauté des développeurs Blockchain

सॉलिडिटी के लिए वेक टेस्टिंग टूल अब ब्लॉकचेन डेव कम्युनिटी के लिए ओपन सोर्स है

Solidity の Wake テスト ツールがブロックチェーン開発コミュニティ向けにオープンソース化されました

Solidity용 Wake 테스트 도구는 이제 블록체인 개발자 커뮤니티를 위해 오픈 소스로 제공됩니다.

A ferramenta Wake Testing for Solidity agora é de código aberto para a comunidade de desenvolvedores Blockchain

Инструмент Wake-тестирования для Solidity теперь открыт для сообщества разработчиков блокчейна

Solidity için Uyanma Testi Aracı Artık Blockchain Geliştirici Topluluğu için Açık Kaynaklı

Công cụ kiểm tra Wake cho Solidity hiện có nguồn mở cho cộng đồng nhà phát triển Blockchain

Solidity 唤醒测试工具现已向区块链开发社区开源

Scientific American, Vol. XXXVII.—No. 2. [New Series.], July 14, 1877 by Various, is part of the HackerNoon Books Series. You can jump to any chapter in this book . BOOT AND SHOE MACHINERY. here BOOT AND SHOE MACHINERY. No manufacturers have taken greater advantage of the ingenuity of the mechanical engineer than the American boot and shoe makers. Nearly every operation in the complex process of evolving finished boots from the plain skins of leather is the object of a special class of machinery; and for several years past, we have weekly chronicled the patenting of several improvements in the devices for effecting some of the numerous operations. We present herewith a series of eight labor-saving machines of the most approved construction, which we select from Knight's "American Mechanical Dictionary."[1] Published in numbers by Messrs. Hurd & Houghton, New York city. Fig. 1 is a shoe-edge trimmer, in which the shoe is mounted on a jack, the carriage of which has a motion of translation and rotation communicated to it: so that, while the side of the sole is being trimmed, the shoe is fed longitudinally against the knife, but at the toe and heel is rotated beneath it. The knife is universally jointed, to permit the hands of the operator to determine the different bevels cut. ![Boot and Shoe Machinery Fig. 2 ](https://cdn.hackernoon.com/images/gQK8BrKBD4ehL3obNS4vfM2m8RB2-i6a3w33.jpeg) Fig. 2 is an ingenious little machine for placing the eyelets of the lace holes in position, and fastening them. The eyelets are fed, one by one, from the reservoir at the top, down the inclined ways, and are seized at the foot between the plunger and anvil, and they are riveted in their proper places in the shoe or strip of leather, which is held and fed by the operator. Fig. 4 is a machine for pressing together the "lifts" which compose a boot or shoe heel, thus dispensing with the handiwork of the hammer and lapstone. The bed is adjusted vertically by a screw to any thickness to which the blank heel may be built; and the plunger is brought down by the depression of the treadle with such force as to compact the lifts together. Fig. 5 shows a heel-pricking machine. When the lifts of the heel are fairly pressed together by the appliance shown in Fig. 4, the pricking machine pierces the necessary holes through all the lifts at once by a gang of awls. The compressed heels are first secured together by tacking, and then placed on the platen; and the plunger, with its gang of awls, descends with great force. Fig. 5 shows a heel-pricking machine. When the lifts of the heel are fairly pressed together by the appliance shown in Fig. 4, the pricking machine pierces the necessary holes through all the lifts at once by a gang of awls. The compressed heels are first secured together by tacking, and then placed on the platen; and the plunger, with its gang of awls, descends with great force. Fig. 6 is a heel trimmer, known in the trade as the Coté trimmer. The shoe is held stationary by the treadle clamp; and the knife stock, which is centrally pivoted to the outer plate or jaw bearing upon the tread lift, is then grasped in the hands of the operator, and moved to give a sweeping cut to trim the heel. Fig. 7 is a machine for pressing boot soles. Beneath the crosshead of the press is a swinging bed, on each end of which is a form, in order that a shoe may remain under pressure upon one while the operator is placing another shoe on the other. The pressure is given by the treadle, which brings down the upper platen on the channeled sole. About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Various (2012). Scientific American, Vol. XXXVII. —No. 2. [New Series.], July 14, 1877. Urbana, Illinois: Project Gutenberg. Retrieved https://www.gutenberg.org/cache/epub/38481/pg38481-images.html This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at , located at . www.gutenberg.org https://www.gutenberg.org/policy/license.html

BOOT AND SHOE MACHINERY

On the Economy of Machinery and Manufactures by Charles Babbage is part of the HackerNoon Books Series. You can jump to any chapter in this book . Of Price as Measured by Money here Chapter 17. Of Price as Measured by Money 201. The money price at which an article sells furnishes us with comparatively little information respecting its value, if we compare distant intervals of time and different countries; for gold and silver, in which price is usually measured, are themselves subject, like all other commodities, to changes in value; nor is there any standard to which these variations can be referred. The average price of a certain quality of different manufactured articles, or of raw produce, has been suggested as a standard; but a new difficulty then presents itself; for the improved methods of producing such articles render their money price extremely variable within very limited periods. The annexed table will afford a striking instance of this kind of change within a period of only twelve years. Prices of the following articles at Birmingham, in the undermentioned years Description 1818 1824 1828 1830 s. d. s. d. s. d. s. d. Anvils cwt 25 0 20 0 16 0 13 0 Awls, polished, Liverpool gross 2 6 2 0 1 6 1 2 Bed-screws, 6 inches long gross 18 0 15 0 6 0 5 0 Bits, tinned. for bridles doz. 5 0 5 0 3 3 2 6 Bolts for doors, 6 inches doz. 6 0 5 0 2 3 1 6 Braces for carpenters, with 12 bits set 9 0 4 0 4 2 3 5 Buttons, for coats gross 4 6 6 3 3 0 2 2 Buttons, small, for waistcoats gross 2 6 2 0 1 2 0 8 Candlesticks, 6 in., brass pair 2 1 1 2 0 1 7 1 2 Curry-combs, six barred doz. 2 9 2 6 1 5 0 1 1 Frying-pans cwt 25 0 21 0 18 0 16 0 Gun-locks, single roller each 6 0 5 2 1 10 1 6 Hammers. shoe, No. 0 doz. 6 9 3 9 3 0 2 9 Description 1818 1824 1828 1830 s. d. s. d. s. d. s. d. Hinges, cast-butts, 1 inch doz. 0 10 0 71/2 0 31/4 0 21/4 Knobs, brass, 2 inches for commodes doz. 4 0 3 6 1 6 1 2 Latches for doors, bright thumb doz. 2 3 2 2 1 0 0 9 Locks for doors, iron rim, 6 inches doz. 38 0 32 0 15 0 13 6 Sad-irons and other castings cwt 22 6 20 0 14 0 11 6 Shovel and tongs, fire-irons pair 1 0 1 0 0 9 0 6 Spoons, tinned table gross 17 6 15 0 10 0 7 0 Stirrups, plated pair 4 6 3 9 1 6 1 1 Trace-chains cwt 28 0 25 0 19 6 16 6 Trays, japanned tea, 30 inches each 4 6 3 0 2 0 1 5 Vices for blacksmiths cwt 30 0 28 0 22 0 19 6 Wire, brass lb. 1 10 1 4 1 0 0 9 —, iron, No. 6 bund. 16 0 13 0 9 0 7 0 202. I have taken some pains to assure myself of the accuracy of the above table: at different periods of the years quoted the prices may have varied; but I believe it may be considered as a fair approximation. In the course of my enquiries I have been favoured with another list, in which many of the same articles occur, but in this last instance the prices quoted are separated by an interval of twenty years. It is extracted from the books of a highly respectable house at Birmingham; and the prices confirm the accuracy of the former table, so far as they relate to the articles which are found in that list. Prices of 1812 and 1832 Reduction per cent in price of Description 1812 1832 1812 s. d. s. d. Anvils cwt 25 0 14 0 44 Awls, Liverpool blades gross 3 6 1 0 71 Candlesticks, iron, plain 3 103/4 2 31/2 41 screwed 6 41/2 3 9 41 Bed screws, 6 inch square head gross 7 6 4 6 40 flat head gross 8 6 4 8 45 Curry-combs, 6 barred dozen 4 01/2 1 0 75 Reduction per cent in price of Description 1812 1832 1812 s. d. s. d. Curry-combs, 8 barred dozen 5 51/2 1 5 74 patent, 6 barred dozen 7 11/2 1 5 80 8 barred dozen 8 63/4 1 10 79 Fire-irons, iron head, No. 1. 1 41/2 0 73/4 53 No. 2 1 6 0 81/2 53 No. 3 1 81/4 0 91/2 53 No. 4 1 101/2 0 101/2 53 Gun-locks, single roller each 7 21/2 1 11 73 Locks, 1 1/4 brass, port. pad 16 0 2 6 85 2 1/2 inch 3 keyed till-locks each 2 2 0 9 65 Shoe tacks gross 5 0 2 0 60 Spoons, tinned, iron table gross 22 6 7 0 69 Stirrups. com. tinned, 2 bar dozen 7 0 2 9 61 Trace-chains, iron cwt 46 91/2 15 0 68 Prices of the principal materials, used in mines in Cornwall, at different periods [I am indebited to Mr John Taylor for this interesting table] ALL DELIVERED AT THE MINES Description 1800 1810 1820 1830 1832 s. d. s. d. s. d. s. d. s. d. Coals wey 81 7 85 5 53 4 51 0 40 0 Timber (balk) foot 2 0 4 0 1 5 1 0 0 10 (oak) foot 3 31/2 3 0 3 6 3 3 Ropes cwt 66 0 84 0 48 6 40 0 40 0 Iron (common bar) cwt 20 6 14 6 11 0 7 0 6 6 Common castings cwt 16 0 15 0 8 0 6 6 Pumps cwt 16s. & 17s. 17s. & 18s. 12s. & 15s. 6 6 6 10 Gunpowder 100 lbs. 114 2 117 6 68 0 52 6 49 0 Candles 9 3 10 0 8 9 5 11 4 10 Tallow cwt 72 0 84 0 65 8 52 6 43 0 Leather lb. 2 4 2 3 24 22 21 Blistered steel cwt 50 0 44 0 38 0 2s. nails cwt 32 0 28 6 22 0 17 0 16 6 203. I cannot omit availing myself of this opportunity of calling the attention of the manufacturers, merchants, and factors, in all our manufacturing and commercial towns, to the great importance, both for their own interests, and for that of the population to which their capital gives employment, of collecting with care such averages from the actual sales registered in their books. Nor, perhaps, would it be without its use to suggest, that such averages would be still more valuable if collected from as many different quarters as possible; that the quantity of the goods from which they are deduced, together with the greatest deviations from the mean, ought to be given; and that if a small committee were to undertake the task, it would give great additional weight to the information. Political economists have been reproached with too small a use of facts, and too large an employment of theory. If facts are wanting, let it be remembered that the closet-philosopher is unfortunately too little acquainted with the admirable arrangements of the factory, and that no class of persons can supply so readily, and with so little sacrifice of time, the data on which all the reasonings of political economists are founded, as the merchant and manufacturer; and, unquestionably, to no class are the deductions to which they give rise so important. Nor let it be feared that erroneous deductions may be made from such recorded facts: the errors which arise from the absence of facts are far more numerous and more durable than those which result from unsound reasoning respecting true data. 204. The great diminution in price of the articles here enumerated may have arisen from several causes: 1. The alteration in the value of the currency. 2. The increased value of gold in consequence of the increased demand for coin. The first of these causes may have had some influence, and the second may have had a very small effect upon the two first quotations of prices, but none at all upon the two latter ones. 3. The diminished rate of profit produced by capital however employed. This may be estimated by the average price of three per cents at the periods stated. 4. The diminished price of the raw materials out of which these articles were manufactured. The raw material is principally brass and iron, and the reduction upon it may, in some measure, be estimated by the diminished price of iron and brass wire, in the cost of which articles, the labour bears a less proportion than it does in many of the others. 5. The smaller quantity of raw material employed, and perhaps, in some instances, an inferior, quality of workmanship. 6. The improved means by which the same effect was produced by diminished labour. 205. In order to afford the means of estimating the influence of these several causes, the following table is subjoined: 1812 1818 1824 1828 1830 1832 Average Price of L s d. L s. d. L s d L s. d L s d L s. d Gold. per oz 4 15 6 4 0 3 17 61/2 3 17 7 3 17 91/2 3 17 10 1/2 Value of currency. per cent 79 5 3 97 6 10 100 100 100 100 Price of 3 per cent consols 591/4 781/4 935/8 86 893/4 821/2 Wheat per quarter 6 5 0 4 1 0 3 2 l 3 1 1 10 3 14 6 2 19 3 English pig iron at Birmingham 7 l0 0 6 7 6 6 l0 0 5 10 0 4 l0 0 English bar iron at Birmingham 10 10 0 9 10 0 7 15 0 6 0 0 5 0 0 Swedish bar iron in London, excluding duty of from L4 to L6 10s per ton 16 10 0 17 10 0 14 0 0 14 10 0 13 15 0 13 2 0 As this table, if unaccompanied by any explanation, might possibly lead to erroneous conclusions, I subjoin the following observations, for which I am indebted to the kindness of Mr Tooke, who may yet, I hope, be induced to continue his valuable work on High and Low Prices, through the important period which has elapsed since its publication. 'The table commences with 1812, and exhibits a great falling off in the price of wheat and iron coincidently with a fall in the price of gold, and leading to the inference of cause and effect. Now, as regards wheat, it so happened that in 1812 it reached its highest price in consequence of a series of bad harvests, when relief by importation was difficult and enormously expensive. In December, 1813, whilst the price of gold had risen to L5, the price of wheat had fallen to 73s., or 50 per cent under what it had been in the spring of 1812; proving clearly that the two articles were under the influence of opposite causes. 'Again, in 1812, the freight and insurance on Swedish iron were so much higher than at present as to account for nearly the whole of the difference of price: and in 1818 there had been an extensive speculation which had raised the price of all iron, so that a part of the subsequent decline was a mere reaction from a previously unfounded elevation. More recently, in 1825, there was a great speculative rise in the article, which served as a strong stimulus to increased production: this, aided by improved power of machinery, has proceeded to such an extent as fully to account for the fall of price.' To these reflections I will only add, that the result of my own observation leads me to believe that by far the most influential of these causes has been the invention of cheaper modes of manufacturing. The extent to which this can be carried, while a profit can yet be realized at the reduced price, is truly astonishing, as the following fact, which rests on good authority, will prove. Twenty years since, a brass knob for the locks of doors was made at Birmingham; the price, at that time, being 13s. 4d. per dozen. The same article is now manufactured, having the same weight of metal, and an equal, or in fact a slightly superior finish, at 1s. 9 1/4d. per dozen. One circumstance which has produced this economy in the manufacture is, that the lathe on which these knobs are finished is now turned by a steam-engine; so that the workman, relieved from that labour, can make them twenty times as fast as he did formerly. 206. The difference of price of the same article, when of various dimensions at different periods in the same country—and in different countries—is curiously contrasted in the annexed table. Comparative price of plate glass, at the manufactories of London, Paris, Berlin, and Petersburg DIMENSIONS LONDON PARIS BERLIN PETERSBURG Height Breadth 1771 1794 1832 1825 1835 1828 1825 in inches in inches L s d L s d L s d L s d L s d L s d L s d 16 16 0103 0101 0176 087 076 081 0410 30 20 146 232 2610 11610 1710 0106 1210 50 30 24 2 4 11 5 0 6 12 10 9 0 5 5 0 3 8 13 0 5 15 0 60 40 67 14 10 27 0 0 13 9 6 22 7 5 10 4 3 21 18 0 12 9 0 76 40 43 6 0 19 2 9 36 4 5 14 17 5 35 2 11 17 5 0 90 50 84 8 0 34 12 9 71 3 8 28 13 4 33 18 7 100 75 275 0 0 74 5 10 210 13 3 70 9 7 120 75 97 15 9 354 3 2 98 3 10 The price of silvering these plates is twenty per cent on the cost price for English glass; ten per cent on the cost price for Paris plates; and twelve and a half on those of Berlin. The following table shews the dimensions and price, when silvered, of the largest plates of glass ever made by the British Plate Glass Company, which are now at their warehouse in London: Height Breadth Price when silvered Inches Inches L s. d. 132 84 200 8 0 146 81 220 7 0 149 84 239 1 6 131 83 239 10 7 160 80 246 15 4 The prices of the largest glass in the Paris lists when silvered, and reduced to English measure, were: Year Inches Inches Price when silvered L s. d. 1825 128 80 629 12 0 1835 128 80 136 19 0 207. If we wish to compare the value of any article at different periods of time, it is clear that neither any one substance, nor even the combination of all manufactured goods, can furnish us with an invariable unit by which to form our scale of estimation. Mr Malthus has proposed for this purpose to consider a day's labour of an agricultural labourer, as the unit to which all value should be referred. Thus, if we wish to compare the value of twenty yards of broad cloth in Saxony at the present time, with that of the same kind and quantity of cloth fabricated in England two centuries ago, we must find the number of days' labour the cloth would have purchased in England at the time mentioned, and compare it with the number of days' labour which the same quantity of cloth will now purchase in Saxony. Agricultural labour appears to have been selected, because it exists in all countries, and employs a large number of persons, and also because it requires a very small degree of previous instruction. It seems, in fact, to be merely the exertion of a man's physical force; and its value above that of a machine of equal power arises from its portability, and from the facility of directing its efforts to arbitrary and continually fluctuating purposes. It may perhaps be worthy of enquiry, whether a more constant average might not be deduced from combining with this species of labour those trades which require but a moderate exertion of skill and which likewise exist in all civilized countries, such as those of the blacksmith and carpenter, etc.(1*) In all such comparisons there is, however, another element, which, though not essentially necessary, will yet add much to our means of judging. It is an estimate of the quantity of that food on which the labourer usually subsists, which is necessary for his daily support, compared with the quantity which his daily wages will purchase. 208. The existence of a class of middlemen, between small producers and merchants, is frequently advantageous to both parties; and there are certain periods in the history of several manufactures which naturally call that class of traders into existence. There are also times when the advantage ceasing, the custom of employing them also terminates; the middlemen, especially when numerous, as they sometimes are in retail trades, enhancing the price without equivalent good. Thus, in the recent examination by the House of Commons into the state of the coal trade, it appears that five-sixths of the London public is supplied by a class of middlemen who are called in the trade Brass plate coal merchants: these consist principally of merchants' clerks, gentlemen's servants, and others, who have no wharfs of their own, but merely give their orders to some true coal merchant, who sends in the coals from his wharf: the brass plate coal merchants, of course, receiving a commission for his agency. 209. In Italy this system is carried to a great extent amongst the voituriers, or persons who undertake to convey travellers. There are some possessed of greater fluency and a more persuasive manner who frequent the inns where the English resort, and who, as soon as they have made a bargain for the conveyance of a traveller, go out amongst their countrymen and procure some other voiturier to do the job for a considerably smaller sum, themselves pocketing the difference. A short time before the day of starting, the contractor appears before his customer in great distress, regretting his inability to perform the journey on account of the dangerous illness of a mother or some relative, and requesting to have his cousin or brother substituted for him. The English traveller rarely fails to acquiesce in this change, and often praises the filial piety of the rogue who has deceived him. NOTES: 1. Much information for such an enquiry is to be found, for the particular period to which it refers, in the Report of the Committee of the House of Commons on Manufacturers' Employment, 2 July, 1830. About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Charles Babbage (2003). On the Economy of Machinery and Manufactures. Urbana, Illinois: Project Gutenberg. Retrieved https://www.gutenberg.org/cache/epub/4238/pg4238.html This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at , located at . www.gutenberg.org https://www.gutenberg.org/policy/license.html

Of Price as Measured by Money

Scientific American Supplement, No. 392, July 7, 1883 by Various, is part of the HackerNoon Books Series. You can jump to any chapter in this book . CAOUTCHOUC. here CAOUTCHOUC. A. Levy contributes the following brief account of this subject to the : Moniteur Scientifique The crude gum cut in irregular strips is passed five or six times between two strong rolls sixteen inches in diameter, and making two or three revolutions per minute. These rolls are kept wet by water trickling on them. This broad strip of gum is perforated with foreign substances and looks like a sieve. It is next put in the cutting machine, a horizontal drum provided with an axle having knives on it. So much heat is produced by this cutting that the water would soon boil if it were not renewed. A second machine of this kind completes the cutting and subdividing, and expels the air and water from it. The mass is then pressed in round or quadrangular blocks. The vulcanization of thin articles from one twenty-fifth to one-sixteenth inch thick, is done by Parkes' patented process, that is, dipping it in carbon disulphide for a short time, to which chloride or bromide of sulphur has been added, and when the solvent has evaporated the sulphur remains behind. Balls, ornamental articles, and surgical apparatus are dipped into melted sulphur at 275° or 300° Fahr. The third most important process consists in mixing in the sulphur mechanically with the gum in the cutting machine. After the pieces have received the form they are to have they are heated with steam or hot air to 275°. Flat articles are vulcanized between press plates heated by steam. This vulcanization is said to have been discovered accidentally by searching different colored stuffs, some of which were dyed yellow with sulphur; the latter stood well. Hard rubber contains more sulphur, and is heated longer and higher. Small or fine tubes and hose are made by a continuous machine that presses it through a hole with a core to it. Large hose is made by wrapping strips around iron rods or tubes. The little air balloons are made in Paris (their value is $300,000) by Brissonet from English Mackintosh cloth. Powdered soapstone is strewed over it in cutting. The edges are united by hammering on a horn anvil, or by machinery through simple adhesion, and the cut surfaces are smooth. About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Various (2005). Scientific American Supplement, No. 392, July 7, 1883. Urbana, Illinois: Project Gutenberg. Retrieved https://www.gutenberg.org/cache/epub/8742/pg8742-images.html This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at , located at . www.gutenberg.org https://www.gutenberg.org/policy/license.html

Levy contributes the following brief account of this subject 

On the Economy of Machinery and Manufactures by Charles Babbage is part of the HackerNoon Books Series. You can jump to any chapter in this book . Increase and Diminution of Velocity here Chapter 4. Increase and Diminution of Velocity 32. The fatigue produced on the muscles of the human frame does not altogether depend on the actual force employed in each effort, but partly on the frequency with which it is exerted. The exertion necessary to accomplish every operation consists of two parts: one of these is the expenditure of force which is necessary to drive the tool or instrument; and the other is the effort required for the motion of some limb of the animal producing the action. In driving a nail into a piece of wood, one of these is lifting the hammer, and propelling its head against the nail; the other is, raising the arm itself, and moving it in order to use the hammer. If the weight of the hammer is considerable, the former part will cause the greatest portion of the exertion. If the hammer is light, the exertion of raising the arm will produce the greatest part of the fatigue. It does therefore happen, that operations requiring very trifling force, if frequently repeated, will tire more effectually than more laborious work. There is also a degree of rapidity beyond which the action of the muscles cannot be pressed. 33. The most advantageous load for a porter who carries wood up stairs on his shoulders, has been investigated by M. Coulomb; but he found from experiment that a man walking up stairs without any load, and raising his burden by means of his own weight in descending, could do as much work in one day, as four men employed in the ordinary way with the most favourable load. 34. The proportion between the velocity with which men or animals move, and the weights they carry, is a matter of considerable importance, particularly in military affairs. It is also of great importance for the economy of labour, to adjust the weight of that part of the animal's body which is moved, the weight of the tool it urges, and the frequency of repetition of these efforts, so as to produce the greatest effect. An instance of the saving of time by making the same motion of the arm execute two operations instead of one, occurs in the simple art of making the tags of bootlaces: these tags are formed out of very thin, tinned, sheet-iron, and were formerly cut out of long strips of that material into pieces of such a breadth that when bent round they just enclosed the lace. Two pieces of steel have recently been fixed to the side of the shears, by which each piece of tinned-iron as soon as it is cut is bent into a semi-cylindrical form. The additional power required for this operation is almost imperceptible, and it is executed by the same motion of the arm which produces the cut. The work is usually performed by women and children; and with the improved tool more than three times the quantity of tags is produced in a given time.(1*) 35. Whenever the work is itself light, it becomes necessary, in order to economize time, to increase the velocity. Twisting the fibres of wool by the fingers would be a most tedious operation: in the common spinning-wheel the velocity of the foot is moderate, but by a very simple contrivance that of the thread is most rapid. A piece of catgut passing round a large wheel, and then round a small spindle, effects this change. This contrivance is common to a multitude of machines, some of them very simple. In large shops for the retail of ribands, it is necessary at short intervals to 'take stock', that is, to measure and rewind every piece of riband, an operation which, even with this mode of shortening it, is sufficiently tiresome, but without it would be almost impossible from its expense. The small balls of sewing cotton, so cheap and so beautifully wound, are formed by a machine on the same principle, and but a few steps more complicated. 36. In turning from the smaller instruments in frequent use to the larger and more important machines, the economy arising from the increase of velocity becomes more striking. In converting cast into wrought-iron, a mass of metal, of about a hundredweight, is heated almost to white heat, and placed under a heavy hammer moved by water or steam power. This is raised by a projection on a revolving axis; and if the hammer derived its momentum only from the space through which it fell, it would require a considerably greater time to give a blow. But as it is important that the softened mass of red-hot iron should receive as many blows as possible before it cools, the form of the cam or projection on the axis is such, that the hammer, instead of being lifted to a small height, is thrown up with a jerk, and almost the instant after it strikes against a large beam, which acts as a powerful spring, and drives it down on the iron with such velocity that by these means about double the number of strokes can be made in a given time. In the smaller tilt-hammers, this is carried still further by striking the tail of the tilt-hammer forcibly against a small steel anvil, it rebounds with such velocity, that from three to five hundred strokes are made in a minute. In the manufacture of anchors, an art in which a similar contrivance is of still greater importance, it has only been recently applied. 37. In the manufacture of scythes, the length of the blade renders it necessary that the workman should move readily, so as to bring every part of it on the anvil in quick succession. This is effected by placing him in a seat suspended by ropes from the ceiling: so that he is enabled, with little bodily exertion, to vary his distance, by pressing his feet against the block which supports the anvil, or against the floor. 38. An increase of velocity is sometimes necessary to render operations possible: thus a person may skate with great rapidity over ice which would not support his weight if he moved over it more slowly. This arises from the fact, that time is requisite for producing the fracture of the ice: as soon as the weight of the skater begins to act on any point, the ice, supported by the water, bends slowly under him; but if the skater's velocity is considerable, he has passed off from the spot which was loaded before the bending has reached the point which would cause the ice to break. 39. An effect not very different from this might take place if very great velocity were communicated to boats. Let us suppose a flatbottomed boat, whose bow forms an inclined plane with the bottom, at rest in still water. If we imagine some very great force suddenly to propel this boat, the inclination of the plane at the forepart would cause it to rise in the water; and if the force were excessive, it might even rise out of the water, and advance, by a series of leaps, like a piece of slate or an oyster shell, thrown as a 'duck and drake'. If the force were not sufficient to pull the boat out of the water, but were just enough to bring its bottom to the surface, it would be carried along with a kind of gliding motion with great rapidity; for at every point of its course it would require a certain time before, it could sink to its usual draft of water; but before that time had elapsed, it would have advanced to another point, and consequently have been raised by the reaction of the water on the inclined plane at its forepart. 40. The same fact, that bodies moving with great velocity have not time to exert the full effect of their weight, seems to explain a circumstance which appears to be very unaccountable. It sometimes happens that when foot-passengers are knocked down by carriages, the wheels pass over them with scarcely any injury, though, if the weight of the carriage had rested on their body, even for a few seconds, it would have crushed them to death. If the view above taken is correct, the injury in such circumstances will chiefly happen to that part of the body which is struck by the advancing wheel. 41. An operation in which rapidity is of essential importance is in bringing the produce of mines up to the surface. The shafts through which the produce is raised are sunk at a very great expense, and it is, of course, desirable to sink as few of them as possible. The matter to be extracted is therefore raised by steam-engines with considerable velocity, and without this many of our mines could not be worked with profit. 42. The effect of great velocity in modifying the form of a cohesive substance is beautifully shown in the process for making window glass, termed "flashing", which is one of the most striking operations in our domestic arts. A workman having dipped his iron tube into the glass pot, and loaded it with several pounds of the melted "metal", blows out a large globe, which is connected with his rod by a short thick hollow neck. Another workman now fixes to the globe immediately opposite to its neck, an iron rod, the extremity of which has been dipped in the melted glass; and when this is firmly attached, a few drops of water separate the neck of the globe from the iron tube. The rod with the globe attached to it is now held at the mouth of a glowing furnace: and by turning the rod the globe is made to revolve slowly, so as to be uniformly exposed to the heat: the first effect of this softening is to make the glass contract upon itself and to enlarge the opening of the neck. As the softening proceeds, the globe is turned more quickly on its axis, and when very soft and almost incandescent, it is removed from the fire, and the velocity of rotation being still continually increased, the opening enlarges from the effect of the centrifugal force, at first gradually, until at last the mouth suddenly expands or "flashes" out into one large circular sheet of red hot glass. The neck of the original globe, which is to become the outer part of the sheet, is left thick to admit of this expansion, and forms the edge of the circular plate of glass, which is called a "Table". The centre presents the appearance of a thick boss or prominence, called the "Bull's-eye", at the part by which it was attached to the iron rod. 43. The most frequent reason for employing contrivances for diminishing velocity, arises from the necessity of overcoming great resistances with small power. Systems of pulleys, the crane, and many other illustrations, might also be adduced here as examples; but they belong more appropriately to some of the other causes which we have assigned for the advantages of machinery. The common smoke-jack is an instrument in which the velocity communicated is too great for the purpose required, and it is transmitted through wheels which reduce it to a more moderate rate. 44. Telegraphs are machines for conveying information over extensive lines with great rapidity. They have generally been established for the purposes of transmitting information during war, but the increasing wants of man will probably soon render them subservient to more peaceful objects. A few years since the telegraph conveyed to Paris information of the discovery of a comet, by M. Gambart, at Marseilles: the message arrived during a sitting of the French Board of Longitude, and was sent in a note from the Minister of the Interior to Laplace, the President, who received it whilst the writer of these lines was sitting by his side. The object in this instance was, to give the earliest publicity to the fact, and to assure to M. Gambart the title of its first discoverer. At Liverpool a system of signals is established for the purposes of commerce, so that each merchant can communicate with his own vessel long before she arrives in the port. NOTES: 1. See Transactions of the Society of Arts, 1826. About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Charles Babbage (2003). On the Economy of Machinery and Manufactures. Urbana, Illinois: Project Gutenberg. Retrieved https://www.gutenberg.org/cache/epub/4238/pg4238.html This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at , located at . www.gutenberg.org https://www.gutenberg.org/policy/license.html

Increase and Diminution of Velocity

On the Economy of Machinery and Manufactures by Charles Babbage is part of the HackerNoon Books Series. You can jump to any chapter in this book . Accumulating Power here Chapter 2. Accumulating Power 20. Whenever the work to be done requires more force for its execution than can be generated in the time necessary for its completion, recourse must be had to some mechanical method of preserving and condensing a part of the power exerted previously to the commencement of the process. This is most frequently accomplished by a fly-wheel, which is in fact nothing more than a wheel having a very heavy rim, so that the greater part of its weight is near the circumference. It requires great power applied for some time to put this into rapid motion; but when moving with considerable velocity, the effects are exceedingly powerful, if its force be concentrated upon a small object. In some of the iron works where the power of the steam-engine is a little too small for the rollers which it drives, it is usual to set the engine at work a short time before the red-hot iron is ready to be removed from the furnace to the rollers, and to allow it to work with great rapidity until the fly has acquired a velocity rather alarming to those unused to such establishments. On passing the softened mass of iron through the first groove, the engine receives a great and very perceptible check; and its speed is diminished at the next and at each succeeding passage, until the iron bar is reduced to such a size that the ordinary power of the engine is sufficient to roll it. 21. The powerful effect of a large flywheel when its force can be concentrated on a point, was curiously illustrated at one of the largest of our manufactories. The proprietor was shewing to a friend the method of punching holes in iron plates for the boilers of steam-engines. He held in his hand a piece of sheet-iron three-eighths of an inch thick, which he placed under the punch. Observing, after several holes had been made, that the punch made its perforations more and more slowly, he called to the engine-man to know what made the engine work so sluggishly, when it was found that the flywheel and punching apparatus had been detached from the steam-engine just at the commencement of his experiment. 22. Another mode of accumulating power arises from lifting a weight and then allowing it to fall. A man, even with a heavy hammer, might strike repeated blows upon the head of a pile without producing any effect. But if he raises a much heavier hammer to a much greater height, its fall, though far less frequently repeated, will produce the desired effect. When a small blow is given to a large mass of matter, as to a pile, the imperfect elasticity of the material causes a small loss of momentum in the transmission of the motion from each particle to the succeeding one; and, therefore, it may happen that the whole force communicated shall be destroyed before it reaches the opposite extremity. 23. The power accumulated within a small space by gunpowder is well known; and, though not strictly an illustration of the subject discussed in this chapter, some of its effects, under peculiar circumstances, are so singular, that an attempt to explain them may perhaps be excused. If a gun is loaded with ball it will not kick so much as when loaded with small shot; and amongst different kinds of shot, that which is the smallest, causes the greatest recoil against the shoulder. A gun loaded with a quantity of sand, equal in weight to a charge of snipe-shot, kicks still more. If, in loading, a space is left between the wadding and the charge, the gun either recoils violently, or bursts. If the muzzle of a gun has accidentally been stuck into the ground, so as to be stopped up with clay, or even with snow, or if it be fired with its muzzle plunged into water, the almost certain result is that it bursts. The ultimate cause of these apparently inconsistent effects is, that every force requires time to produce its effect; and if the time requisite for the elastic vapour within to force out the sides of the barrel, is less than that in which the condensation of the air near the wadding is conveyed in sufficient force to drive the impediment from the muzzle, then the barrel must burst. If sometimes happens that these two forces are so nearly balanced that the barrel only swells; the obstacle giving way before the gun is actually burst. The correctness of this explanation will appear by tracing step by step the circumstances which arise on discharging a gun loaded with powder confined by a cylindrical piece of wadding, and having its muzzle filled with clay, or some other substance having a moderate degree of resistance. In this case the first effect of the explosion is to produce an enormous pressure on everything confining it, and to advance the wadding through a very small space. Here let us consider it as at rest for a moment, and examine its condition. The portion of air in immediate contact with the wadding is condensed; and if the wadding were to remain at rest, the air throughout the tube would soon acquire a uniform density. But this would require a small interval of time; for the condensation next the wadding would travel with the velocity of sound to the other end, from whence, being reflected back, a series of waves would be generated, which, aided by the friction of the tube, would ultimately destroy the motion. But until the first wave reaches the impediment at the muzzle, the air can exert no pressure against it. Now if the velocity communicated to the wadding is very much greater than that of sound, the condensation of the air immediately in advance of it may be very great before the resistance transmitted to the muzzle is at all considerable; in which case the mutual repulsion of the particles of air so compressed, will offer an absolute barrier to the advance of the wadding.(1*) If this explanation be correct, the additional recoil, when a gun is loaded with small shot or sand, may arise in some measure from the condensation of the air contained between their particles; but chiefly from the velocity communicated by the explosion to those particles of the substances in immediate contact with the powder being greater than that with which a wave can be transmitted through them. It also affords a reason for the success of a method of blasting rocks by filling the upper part of the hole above the powder with sand, instead of clay rammed hard. That the destruction of the gun barrel does not arise from the property possessed by fluids, and in some measure also by sand and small shot, of pressing equally in all directions, and thus exerting a force against a large portion of the interior surface, seems to be proved by a circumstance mentioned by Le Vaillant and other travellers, that, for the purpose of taking birds without injuring their plumage, they filled the barrel of their fowling pieces with water, instead of loading them with a charge of shot. 24. The same reasoning explains a curious phenomenon which occurs in firing a still more powerfully explosive substance. If we put a small quantity of fulminating silver upon the face of an anvil, and strike it slightly with a hammer, it explodes; but instead of breaking either the hammer or the anvil, it is found that that part of the face of each in contact with the fulminating silver is damaged. In this case the velocity communicated by the elastic matter disengaged may be greater than the velocity of a wave traversing steel; so that the particles at the surface are driven by the explosion so near to those next adjacent, that when the compelling force is removed, the repulsion of the particles within the mass drives back those nearer to the surface, with such force, that they pass beyond the limits of attraction, and are separated in the shape of powder. 25. i) The success of the experiment of firing a tallow candle through a deal board, would be explained in the same manner, by supposing the velocity of a wave propagated through deal to be greater than that of a wave passing through tallow. 25. ii) The boiler of a steam-engine sometimes bursts even during the escape of steam through the safety-valve. If the water in the boiler is thrown upon any part which happens to be red hot, the steam formed in the immediate neighbourhood of that part expands with greater velocity than that with which a wave can be transmitted through the less heated steam; consequently one particle is urged against the next, and an almost invincible obstacle is formed, in the same manner as described in the case of the discharge of a gun. If the safety-valve is closed, it may retain the pressure thus created for a short time, and even when it is open the escape may not be sufficiently rapid to remove all impediment; there may therefore exist momentarily within the boiler pressures of various force, varying from that which can just lift the safety-valve up to that which is sufficient, if exerted during an extremely small space of time, to tear open the boiler itself. 26. This reasoning ought, however, to be admitted with caution; and perhaps some inducement to examine it carefully may be presented by tracing it to extreme cases. It would seem, but this is not a necessary consequence, that a gun might be made so long, that it would burst although no obstacle filled up its muzzle. It should also follow that if, after the gun is charged, the air were extracted from the barrel, though the muzzle be then left closed, the gun ought not to burst. It would also seem to follow from the principle of the explanation, that a body might be projected in air, or other elastic resisting medium, with such force that, after advancing a very short space it should return in the same direction in which it was projected. NOTES: 1. See Poisson's remarks, Ecole Polytec. Cahier, xxi, p. 191. About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Charles Babbage (2003). On the Economy of Machinery and Manufactures. Urbana, Illinois: Project Gutenberg. Retrieved https://www.gutenberg.org/cache/epub/4238/pg4238.html This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at , located at . www.gutenberg.org https://www.gutenberg.org/policy/license.html

Accumulating Power

How it Works by Archibald Williams is part of the HackerNoon Books Series. You can jump to any chapter in this book . WIRELESS TELEGRAPHY. here Chapter VII. WIRELESS TELEGRAPHY. The transmitting apparatus—The receiving apparatus—Syntonic transmission—The advance of wireless telegraphy. IN our last chapter we reviewed briefly some systems of sending telegraphic messages from one point of the earth's surface to another through a circuit consisting partly of an insulated wire and partly of the earth itself. The metallic portion of a long circuit, especially if it be a submarine cable, is costly to install, so that in quite the early days of telegraphy efforts were made to use the ether in the place of wire as one conductor. When a hammer strikes an anvil the air around is violently disturbed. This disturbance spreads through the molecules of the air in much the same way as ripples spread from the splash of a stone thrown into a pond. When the sound waves reach the ear they agitate the tympanum, or drum membrane, and we "hear a noise." The hammer is here the transmitter, the air the conductor, the ear the receiver. In wireless telegraphy we use the ether as the conductor of electrical disturbances. Marconi, Slaby, Branly, Lodge, De Forest, Popoff, and others have invented apparatus for causing disturbances of the requisite kind, and for detecting their presence. The main features of a wireless telegraphy outfit are shown in Figs. 59 and 61. THE TRANSMITTER APPARATUS. We will first consider the transmitting outfit (Fig. 59). It includes a battery, dispatching key, and an induction coil having its secondary circuit terminals connected with two wires, the one leading to an earth-plate, the other carried aloft on poles or suspended from a kite. In the large station at Poldhu, Cornwall, for transatlantic signalling, there are special wooden towers 215 feet high, between which the aërial wires hang. At their upper and lower ends respectively the earth and aërial wires terminate in brass balls separated by a gap. When the operator depresses the key the induction coil charges these balls and the wires attached thereto with high-tension electricity. As soon as the quantity collected exceeds the resistance of the air-gap, a discharge takes place between the balls, and the ether round the aërial wire is violently disturbed, and waves of electrical energy are propagated through it. The rapidity with which the discharges follow one another, and their travelling power, depends on the strength of the induction coil, the length of the air-gap, and the capacity of the wires. RECEIVING APPARATUS. The human body is quite insensitive to these etheric waves. We cannot feel, hear, or see them. But at the receiving station there is what may be called an "electric eye." Technically it is named a . A Marconi coherer is seen in Fig. 60. Inside a small glass tube exhausted of air are two silver plugs, p p, carrying terminals, t t, projecting through the glass at both ends. A small gap separates the plugs at the centre, and this gap is partly filled with nickel-silver powder. If the terminals of the coherer are attached to those of a battery, practically no current will pass under ordinary conditions, as the particles of nickel-silver touch each other very lightly and make a "bad contact." But if the coherer is also attached to wires leading into the earth and air, and ether waves strike those wires, at every impact the particles will cohere—that is, pack tightly together—and allow battery current to pass. The property of cohesion of small conductive bodies when influenced by Hertzian waves was first noticed in 1874 by Professor D.E. Hughes while experimenting with a telephone. coherer We are now in a position to examine the apparatus of which a coherer forms part (Fig. 61). First, we notice the aërial and earth wires, to which are attached other wires from battery a. This battery circuit passes round the relay magnet r and through two choking coils, whose function is to prevent the Hertzian waves entering the battery. The relay, when energized, brings contact d against e and closes the circuit of battery b, which is much more powerful than battery a, and operates the magnet m as well as the , which is practically an electric bell minus the gong. (The tapper circuit is indicated by the dotted lines.) tapper We will suppose the transmitter of a distant station to be at work. The electric waves strike the aërial wire of the receiving station, and cause the coherer to cohere and pass current. The relay is closed, and both tapper and Morse inker begin to work. The tapper keeps striking the coherer and shakes the particles loose after every cohesion. If this were not done the current of a would pass continuously after cohesion had once taken place. When the key of the transmitter is pressed down, the waves follow one another very quickly, and the acquired conductivity of the coherer is only momentarily destroyed by the tap of the hammer. During the impression of a dot by the Morse inker, contact is made and broken repeatedly; but as the armature of the inker is heavy and slow to move it does not vibrate in time with the relay and tapper. Therefore the Morse instrument reproduces in dots and dashes the short and long depressions of the key at the transmitting station, while the tapper works rapidly in time with the relay. The Morse inker is shown diagrammatically. While current passes through m the armature is pulled towards it, the end p, carrying an inked wheel, rises, and a mark is made on the tape w, which is moved continuously being drawn forward off reel r by the clockwork—or electrically-driven rollers r1 r2. SYNTONIC TRANSMISSION. If a number of transmitting stations are sending out messages simultaneously, a jumble of signals would affect all the receivers round, unless some method were employed for rendering a receiver sensitive only to the waves intended to influence it. Also, if distinction were impossible, even with one transmitter in action its message might go to undesired stations. There are various ways of "tuning" receivers and transmitters, but the principle underlying them all is analogous to that of mechanical vibration. If a weight is suspended from the end of a spiral spring, and given an upward blow, it bobs up and down a certain number of times per minute, every movement from start to finish having exactly the same duration as the rest. The resistance of the air and the internal friction of the spring gradually lessen the amplitude of the movements, and the weight finally comes to rest. Suppose that the weight scales 30 lbs., and that it naturally bobs twenty times a minute. If you now take a feather and give it a push every three seconds you can coax it into vigorous motion, assuming that every push catches it exactly on the rebound. The same effect would be produced more slowly if 6 or 9 second intervals were substituted. But if you strike it at 4, 5, or 7 second intervals it will gradually cease to oscillate, as the effect of one blow neutralizes that of another. The same phenomenon is witnessed when two tuning-forks of equal pitch are mounted near one another, and one is struck. The other soon picks up the note. But a fork of unequal pitch would remain dumb. Now, every electrical circuit has a "natural period of oscillation" in which its electric charge vibrates. It is found possible to "tune," or "syntonize," the aërial rod or wire of a receiving station with a transmitter. A vertical wire about 200 feet in length, says Professor J.A. Fleming, has a natural time period of electrical oscillation of about one-millionth of a second. Therefore if waves strike this wire a million times a second they will reinforce one another and influence the coherer; whereas a less or greater frequency will leave it practically unaffected. By adjusting the receiving circuit to the transmitter, or , selective wireless telegraphy becomes possible. vice versâ ADVANCE OF WIRELESS TELEGRAPHY. The history of wireless telegraphy may be summed up as follows:— 1842.—Professor Morse sent aërial messages across the Susquehanna River. A line containing a battery and transmitter was carried on posts along one bank and "earthed" in the river at each end. On the other bank was a second wire attached to a receiver and similarly earthed. Whenever contact was made and broken on the battery side, the receiver on the other was affected. Distance about 1 mile. 1859.—James Bowman Lindsay transmitted messages across the Tay at Glencarse in a somewhat similar way. Distance about ½ mile. 1885.—Sir William Preece signalled from Lavernock Point, near Cardiff, to Steep Holm, an island in the Bristol Channel. Distance about 5½ miles. In all these electrical of current was employed. induction 1886.—Hertzian waves discovered. 1895.—Professor A. Popoff sent Hertzian wave messages over a distance of 3 miles. 1897.—Marconi signalled from the Needles Hotel, Isle of Wight, to Swanage; 17½ miles. 1901.—Messages sent at sea for 380 miles. 1901, Dec. 17.—Messages transmitted from Poldhu, Cornwall, to Hospital Point, Newfoundland; 2,099 miles. Mr. Marconi has so perfected tuning devices that his transatlantic messages do not affect receivers placed on board ships crossing the ocean, unless they are purposely tuned. Atlantic liners now publish daily small newspapers containing the latest news, flashed through space from land stations. In the United States the De Forest and Fessenden systems are being rapidly extended to embrace the most out-of-the-way districts. Every navy of importance has adopted wireless telegraphy, which, as was proved during the Russo-Japanese War, can be of the greatest help in directing operations. About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Archibald Williams (2009). How it Works. Urbana, Illinois: Project Gutenberg. Retrieved https://www.gutenberg.org/cache/epub/28553/pg28553-images.html This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at , located at . www.gutenberg.org https://www.gutenberg.org/policy/license.html

WIRELESS TELEGRAPHY.

WORKSHOP MACHINERY

Quite possibly, nothing in is more critical—and difficult to do well—than smart contract testing. For individual developers and small teams, the requisite testing tools are often too expensive and hard to use. Fortunately, a new breed of testing techniques is emerging, ones that are both affordable and accessible. Web3 In my , I talked about one of the most popular techniques: fuzzing. Fuzzing is a dynamic testing technique capable of identifying errors and vulnerabilities that standard tests don’t typically identify. I also talked about how one of the most powerful fuzzing tools— —just released support for one of the most powerful development frameworks: . This combination complements your manual audits by providing new vulnerability detection techniques that you can use to avoid costly contract rewrites. previous article Diligence Fuzzing Foundry Last time, we looked at Diligence and Foundry in detail and how they worked together. This time, we’ll review why the integration is a big deal . and then run through a detailed tutorial on exactly how to implement fuzzing with Diligence Fuzzing and Foundry Why Fuzzing Is Important As even novice dApp developers know, smart contracts running on blockchains tend to be . In other words, if you deploy a contract and someone (including yourself) discovers a security loophole, there’s nothing you can do to prevent a malicious party from exploiting that weakness. So deploying defect-free contracts is incredibly important. immutable Projects that handle the flow of assets of enormous value, therefore, typically spend thousands of dollars and many months auditing and stress testing their contracts. is a testing method that can supplement your testing practice and find defects that otherwise would have made it to production. Fuzzing works by inputting millions of invalid, unexpected, or (semi) random data points into your smart contract to cause unexpected behavior and stress test the code. The fuzzing tool identifies vulnerabilities and flags anything that doesn’t meet expectations through the Fuzzing dashboard. It’s an incredible tool for identifying edge cases that could result in those dreaded and expensive smart contract hacks. Fuzzing is a (FaaS) offering by ConsenSys, inspired by coverage-based fuzzing approaches like AFL and libFuzzer. Released in closed beta earlier this year, Diligence Fuzzing has routinely outperformed its counterparts in terms of overall code coverage, time to coverage, and number of bugs found. Diligence Fuzzing Fuzzing as a Service is an development—and probably the most popular. With Foundry, you can create smart contracts, deploy, and more. Foundry open-source framework for Ethereum The ability to use Diligence Fuzzing with Foundry was just recently released, pairing the leading fuzzing tool with the lead development framework. So, let’s jump into how easy it is to use the combination to test your Ethereum smart contracts. Testing an Ethereum Smart Contract with Foundry and Diligence Fuzzing Step 1: Install Python and Node The tools we are using in this tutorial are extremely diverse. In order to install Diligence Fuzzing, we will require Python and pip. You can do so by following the instructions available for your OS . here Check that they’ve been installed correctly by running the following commands: $ python --version$ pip --version Next, let’s install Node and npm using the and check their version numbers by running: instructions available here $ node -v$ npm -v Step 2: Create a Foundry Project Let’s now create a Foundry project! First, let’s install Foundryup, a package that will make installing Foundry a breeze. (Without it, we would have to build Foundry from source using Rust and Cargo.) $ curl -L https://foundry.paradigm.xyz | bash Finally, let’s install Foundry by simply running: $ foundryup If all goes well, you should see a downloading screen in your terminal that looks something like this: .xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx  ╔═╗ ╔═╗ ╦ ╦ ╔╗╔ ╔╦╗ ╦═╗ ╦ ╦         Portable and modular toolkit ╠╣  ║ ║ ║ ║ ║║║  ║║ ╠╦╝ ╚╦╝    for Ethereum Application Development  ╚   ╚═╝ ╚═╝ ╝╚╝ ═╩╝ ╩╚═  ╩                 written in Rust. .xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx Repo       : https://github.com/foundry-rs/Book       : https://book.getfoundry.sh/                      Chat       : https://t.me/foundry_rs/                         Support    : https://t.me/foundry_support/Contribute : https://github.com/orgs/foundry-rs/projects/2/ .xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx.xOx foundryup: installing foundry (version nightly, tag nightly-6672134672c8e442684d7d9c51fa8f8717b0f600)foundryup: downloading latest forge, cast, anvil, and chisel Out of the tools that Foundryup installs for us, the one we’re most interested in is Forge. Using forge, we can initialize a sample Foundry project as follows: $ forge init fuzz_project This will create a new folder in your repository called Open the project in your favorite code editor (like VS Code). fuzz_project. Step 3: Compile Contract and Perform Normal Testing One of the main reasons Foundry has witnessed a monumental rise in popularity is because of its focus on testing. Foundry is one of the very few frameworks that allow developers to test Solidity smart contracts using Solidity itself (instead of a JavaScript testing framework like Chai or Mocha). In the sample project that Foundry has created for us, you will find a sample contract in the folder and a test contract in the folder.\ src/ test/ The main contract is extremely basic. It allows you to set a number and increment that number. // SPDX-License-Identifier: UNLICENSEDpragma solidity ^0.8.13; contract Counter {    uint256 public number; function setNumber(uint256 newNumber) public {        number = newNumber;    } function increment() public {        number++;    }} Now, let’s take a look at the corresponding test contract. // SPDX-License-Identifier: UNLICENSEDpragma solidity ^0.8.13; import {Test, console2} from "forge-std/Test.sol";import {Counter} from "../src/Counter.sol";  contract CounterTest is Test {    Counter public counter; function setUp() public {        counter = new Counter();        counter.setNumber(0);    } function testIncrement() public {        counter.increment();        assertEq(counter.number(), 1);    } function testSetNumber(uint256 x) public {        counter.setNumber(x);        assertEq(counter.number(), x);    }} Notice how simple this is in contrast to the huge amount of boilerplate you’re required to write while testing contracts using JS frameworks. Testing is also extremely simple. All you have to do is run… $ forge test …to get output that looks something like this: [⠢] Compiling...[⠑] Compiling 22 files with 0.8.21[⠊] Solc 0.8.21 finished in 3.60sCompiler run successful! Running 2 tests for test/Counter.t.sol:CounterTest[PASS] testIncrement() (gas: 28334)[PASS] testSetNumber(uint256) (runs: 256, μ: 27398, ~: 28409)Test result: ok. 2 passed; 0 failed; 0 skipped; finished in 8.32msRan 1 test suites: 2 tests passed, 0 failed, 0 skipped (2 total tests) Step 4: Install Diligence Fuzzing In order to perform Diligence Fuzzing in our Foundry project, we will need to install it first. This is extremely simple to do. Run the following command: $ pip3 install diligence-fuzzing Just installing the CLI tool is not enough, though. In order to perform fuzzing, we will require an API key from ConsenSys. To obtain this, create a . Next, choose a subscription tier that meets your needs. For this tutorial, the free tier should be more than sufficient. free Diligence Fuzzing account Once you’ve created an account, you will be redirected to a dashboard that looks something like this: Next, create an API key . You can name the key anything you want.\ here Once the key is created, keep it handy. We will require it in a later step. Step 5: Perform Diligence Fuzzing Believe it or not, performing fuzzing, one of the most advanced testing techniques for Web3 ever created, can be done using a single command. And by using Diligence, you seamlessly pick up the foundry fuzz tests and start fuzzing without any additional work. $ fuzz forge test -k <your_api_key> If all goes well, you should see an output that looks something like this: 🛠️  Parsing foundry config🛠️  Compiling tests🛠️  Collecting tests🛠️  Collecting and validating campaigns for submission🛠️  Preparing the seed state⚡️ Submitting campaignsYou can view campaign here: https://fuzzing.diligence.tools/campaigns/cmp_a39a98d29554496b91f4a977804d468dDone 🎉 You can obtain detailed information about your test results by visiting the campaign above. It should look something like this: Conclusion Fuzzing with Diligence Fuzzing and Foundry makes it easy to add powerful fuzzing to your testing tools. With it, you should be able to catch many of the pressing vulnerabilities that may plague your smart contracts. With this integration, in fact, there’s no reason to include fuzzing in your workflows. not Also published . here

Prevent Smart Contract Vulnerabilities through Fuzz Testing

Foundry is a smart contract development toolchain for Ethereum written in rust. Foundry simplifies the development and deployment of smart contracts. It streamlines the process by managing dependencies, running tests, and facilitating deployment. In this article, we will explore the following: What is Foundry, and why should you use it? Different tools provided by Foundry for smart contract development How to get started with Foundry: create, deploy and test smart contracts in Solidity Let's dive right in! About Foundry Foundry is a smart contract development toolchain for Ethereum written in rust. Foundry manages your dependencies, compiles your project, runs tests, deploys, and lets you interact with the chain from the command-line and via Solidity scripts. Foundry is created by an investment firm focused on crypto. Paradigm, Why use Foundry? You can write tests for your smart contract in Solidity (when using other smart contract development frameworks like Hardhat or Truffle, you would test Solidity using JavaScript or TypeScript). You can read why you should be writing tests in Solidity here. Foundry has a powerful built-in fuzzing capability. Fuzzing, in essence, is a technique used to find vulnerabilities or bugs in software by providing random, unexpected inputs to the program. Fuzzing lets the Solidity test runner choose the arguments for you randomly, by simply giving arguments to your Solidity test function. Foundry also provides you with different tools for smart contract development: tests, builds, and deploys your smart contracts. Forge: Foundry's CLI tool for performing Ethereum RPC calls. You can make smart contract calls, send transactions, or retrieve any type of chain data. Cast: : local testnet node shipped with Foundry. You can use it for testing your contracts from frontends or for interacting over RPC. Anvil an advanced Solidity REPL shipped with Foundry. It can be used to quickly test the behaviour of Solidity snippets on a local or forked network. Chisel: You can explore more about Foundry toolkit from the and the . Foundry Book GitHub repo Also, a list of Foundry resources including tools, tutorials, libraries & projects using Foundry. here's You can read more about the comparison between the Foundry and Hardhat smart contract development toolkit . here Building, testing and Deploying Smart contracts with Foundry Installation On Linux and macOS: Open your terminal and run the following command: curl -L https://foundry.paradigm.xyz | bash This will install Foundryup, then simply follow the instructions on-screen, which will make the command available in your CLI. foundryup Now run the command in the terminal to install Foundry toolchain: foundryup foundryup On Windows: If you're on Windows, you will need to install and use or , as your terminal, since Foundryup currently does not support Powershell or Cmd. Git BASH WSL Initialize the project To start a new project with Foundry, use : forge init forge init foundry_project This will generate a new project folder called . The folder will contain the following: foundry_project default directory for your smart contracts src: default directory for tests tests: foundry project configuration file foundry.toml: contains the dependencies lib: solidity scripting files script: Inside the folder, you'll find an included sample smart contract named . src Counter.sol // SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.13;

contract Counter {
    uint256 public number;

    function setNumber(uint256 newNumber) public {
        number = newNumber;
    }

    function increment() public {
        number++;
    }
} To compile the smart contract use : forge build forge build If your contract compiles successfully, you will see the following output in your terminal: This will compile the smart contracts in the folder and also create a new folder named which will contain the bytecode of the compiled contract. src out Testing the contract Foundry generates a directory named , which is the default folder for storing all the tests for smart contracts. The name of the test files has an extension of tests .t.sol If you navigate into the test folder, you'll come across a specifically named test file called . Counter.t.sol // SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.13;

import "forge-std/Test.sol";
import "../src/Counter.sol";

contract CounterTest is Test {
    Counter public counter;

    function setUp() public {
        counter = new Counter();
        counter.setNumber(0);
    }

    function testIncrement() public {
        counter.increment();
        assertEq(counter.number(), 1);
    }

    function testSetNumber(uint256 x) public {
        counter.setNumber(x);
        assertEq(counter.number(), x);
    }
} To run this file to test the smart contract use : Couter.sol forge test forge test If all the test passes then you will see the following output in your terminal: You can also see the gas cost being printed for the functions in the test contract. On the other hand if some tests fail, this will be the output. You can replicate this by make some changes in the smart contract(I've changed the function so that it increments the number by 2 instead of 1). Counter.sol increment function increment() public {
    number += 2;
} Deploying the smart contract To deploy the smart contract tot a network use command: forge create forge create --rpc-url <your_rpc_endpoint> --private-key <wallet_private_key> src/Counter.sol:Counter You can get the RPC for the network from Alchemy by following this guide . If the smart contract is deployed successfully you will see the following output in your terminal: Writing tests for smart contract Now let's add some of our own functions and tests to the existing smart contract. Counter.sol // SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.13;

contract Counter {
    uint256 public number;
    uint256 public myNumber = 42;

    function setNumber(uint256 newNumber) public {
        number = newNumber;
    }

    function increment() public {
        number++;
    }

    function decrement() public {
        myNumber--;
    }
} In the above smart contract we have added variable which has a value of 42 and the function which decrements the value of by 1. myNumber decrement() myNumber To test these functions we need to add some functions in the test file. Counter.t.sol // SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.13;

import "forge-std/Test.sol";
import "../src/Counter.sol";

contract CounterTest is Test {
    Counter public counter;

    function setUp() public {
        counter = new Counter();
        counter.setNumber(0);
    }

    function testIncrement() public {
        counter.increment();
        assertEq(counter.number(), 1);
    }

    function testSetNumber(uint256 x) public {
        counter.setNumber(x);
        assertEq(counter.number(), x);
    }

    function testMyNumber() public {
        assertEq(counter.myNumber(), 42);
    }

    function testDecrement() public {
        counter.decrement();
        assertEq(counter.myNumber(), 41);
    }
} In the above test file we have added test functions and . The function checks the assigned value of and function checks the working of the decrement function. Both of these functions use to equate the value assigned to . testMyNumber() testDecrement() testMyNumber() myNumber testDecrement() assertEq myNumber Now let's run these new tests with the command: forge test forge test If all the test passes you will get the following output in your terminal: As you can see all the test passed, and we also got the amount of gas used to run each test function. Using libraries The libraries that you install will go in the folder , of your project by default, is installed, this one allows you to run tests, create asserts or logs. If you want to install other libraries(e.g. openzeppelin) you can run: lib ds-test forge install openzeppelin/openzeppelin-contracts This will add the openzeppelin repository in your project under the folder. Now you can import and use the openzeppelin smart contracts in your project. lib/openzeppelin-contracts Next Steps With this we have learned the most basic applications of the foundry toolkit. Further we will learn how to develop, test and deploy more complex contracts like ERC20, ERC721 tokens, DEXs and many more using foundry. Hope you enjoyed the article! If you have any questions or comments, feel free to drop them below or reach out to me on: Twitter LinkedIn Also published . here

Introduction to Smart Contract Development Using Foundry

The Mysterious Island by Jules Verne, is part of the HackerNoon Books Series. You can jump to any chapter in this book . Chapter XV here Chapter XV The next day, the 17th of April, the sailor’s first words were addressed to Gideon Spilett. “Well, sir,” he asked, “what shall we do to-day?” “What the captain pleases,” replied the reporter. Till then the engineer’s companions had been brickmakers and potters, now they were to become metallurgists. The day before, after breakfast, they had explored as far as the point of Mandible Cape, seven miles distant from the Chimneys. There, the long series of downs ended, and the soil had a volcanic appearance. There were no longer high cliffs as at Prospect Heights, but a strange and capricious border which surrounded the narrow gulf between the two capes, formed of mineral matter, thrown up by the volcano. Arrived at this point the settlers retraced their steps, and at nightfall entered the Chimneys; but they did not sleep before the question of knowing whether they could think of leaving Lincoln Island or not was definitely settled. The twelve hundred miles which separated the island from the Pomoutous Island was a considerable distance. A boat could not cross it, especially at the approach of the bad season. Pencroft had expressly declared this. Now, to construct a simple boat even with the necessary tools, was a difficult work, and the colonists not having tools they must begin by making hammers, axes, adzes, saws, augers, planes, etc., which would take some time. It was decided, therefore, that they would winter at Lincoln Island, and that they would look for a more comfortable dwelling than the Chimneys, in which to pass the winter months. Before anything else could be done it was necessary to make the iron ore, of which the engineer had observed some traces in the northwest part of the island, fit for use by converting it either into iron or into steel. Metals are not generally found in the ground in a pure state. For the most part they are combined with oxygen or sulphur. Such was the case with the two specimens which Cyrus Harding had brought back, one of magnetic iron, not carbonated, the other a pyrite, also called sulphuret of iron. It was, therefore the first, the oxide of iron, which they must reduce with coal, that is to say, get rid of the oxygen, to obtain it in a pure state. This reduction is made by subjecting the ore with coal to a high temperature, either by the rapid and easy Catalan method, which has the advantage of transforming the ore into iron in a single operation, or by the blast furnace, which first smelts the ore, then changes it into iron, by carrying away the three to four per cent. of coal, which is combined with it. Now Cyrus Harding wanted iron, and he wished to obtain it as soon as possible. The ore which he had picked up was in itself very pure and rich. It was the oxydulous iron, which is found in confused masses of a deep gray color; it gives a black dust, crystallized in the form of the regular octahedron. Native lodestones consist of this ore, and iron of the first quality is made in Europe from that with which Sweden and Norway are so abundantly supplied. Not far from this vein was the vein of coal already made use of by the settlers. The ingredients for the manufacture being close together would greatly facilitate the treatment of the ore. This is the cause of the wealth of the mines in Great Britain, where the coal aids the manufacture of the metal extracted from the same soil at the same time as itself. “Then, captain,” said Pencroft, “we are going to work iron ore?” “Yes, my friend,” replied the engineer, “and for that—something which will please you—we must begin by having a seal hunt on the islet.” “A seal hunt!” cried the sailor, turning towards Gideon Spilett. “Are seals needed to make iron?” “Since Cyrus has said so!” replied the reporter. But the engineer had already left the Chimneys, and Pencroft prepared for the seal hunt, without having received any other explanation. Cyrus Harding, Herbert, Gideon Spilett, Neb, and the sailor were soon collected on the shore, at a place where the channel left a ford passable at low tide. The hunters could therefore traverse it without getting wet higher than the knee. Harding then put his foot on the islet for the first, and his companions for the second time. On their landing some hundreds of penguins looked fearlessly at them. The hunters, armed with sticks, could have killed them easily, but they were not guilty of such useless massacre, as it was important not to frighten the seals, who were lying on the sand several cable lengths off. They also respected certain innocent-looking birds, whose wings were reduced to the state of stumps, spread out like fins, ornamented with feathers of a scaly appearance. The settlers, therefore, prudently advanced towards the north point, walking over ground riddled with little holes, which formed nests for the sea-birds. Towards the extremity of the islet appeared great black heads floating just above the water, having exactly the appearance of rocks in motion. These were the seals which were to be captured. It was necessary, however, first to allow them to land, for with their close, short hair, and their fusiform conformation, being excellent swimmers, it is difficult to catch them in the sea, while on land their short, webbed feet prevent their having more than a slow, waddling movement. Pencroft knew the habits of these creatures, and he advised waiting till they were stretched on the sand, when the sun, before long, would send them to sleep. They must then manage to cut off their retreat and knock them on the head. The hunters, having concealed themselves behind the rocks, waited silently. An hour passed before the seals came to play on the sand. They could count half a dozen. Pencroft and Herbert then went round the point of the islet, so as to take them in the rear, and cut off their retreat. During this time Cyrus Harding, Spilett, and Neb, crawling behind the rocks, glided towards the future scene of combat. All at once the tall figure of the sailor appeared. Pencroft shouted. The engineer and his two companions threw themselves between the sea and the seals. Two of the animals soon lay dead on the sand, but the rest regained the sea in safety. “Here are the seals required, captain!” said the sailor, advancing towards the engineer. “Capital,” replied Harding. “We will make bellows of them!” “Bellows!” cried Pencroft. “Well! these are lucky seals!” It was, in fact, a blowing-machine, necessary for the treatment of the ore that the engineer wished to manufacture with the skins of the amphibious creatures. They were of a medium size, for their length did not exceed six feet. They resembled a dog about the head. As it was useless to burden themselves with the weight of both the animals, Neb and Pencroft resolved to skin them on the spot, while Cyrus Harding and the reporter continued to explore the islet. The sailor and the Negro cleverly performed the operation, and three hours afterwards Cyrus Harding had at his disposal two seals’ skins, which he intended to use in this state, without subjecting them to any tanning process. The settlers waited till the tide was again low, and crossing the channel they entered the Chimneys. The skins had then to be stretched on a frame of wood and sewn by means of fibers so as to preserve the air without allowing too much to escape. Cyrus Harding had nothing but the two steel blades from Top’s collar, and yet he was so clever, and his companions aided him with so much intelligence, that three days afterwards the little colony’s stock of tools was augmented by a blowing-machine, destined to inject the air into the midst of the ore when it should be subjected to heat—an indispensable condition to the success of the operation. On the morning of the 20th of April began the “metallic period,” as the reporter called it in his notes. The engineer had decided, as has been said, to operate near the veins both of coal and ore. Now, according to his observations, these veins were situated at the foot of the northeast spurs of Mount Franklin, that is to say, a distance of six miles from their home. It was impossible, therefore, to return every day to the Chimneys, and it was agreed that the little colony should camp under a hut of branches, so that the important operation could be followed night and day. This settled, they set out in the morning. Neb and Pencroft dragged the bellows on a hurdle; also a quantity of vegetables and animals, which they besides could renew on the way. The road led through Jacamar Wood, which they traversed obliquely from southeast to northwest, and in the thickest part. It was necessary to beat a path, which would in the future form the most direct road to Prospect Heights and Mount Franklin. The trees, belonging to the species already discovered, were magnificent. Herbert found some new ones, among others some which Pencroft called “sham leeks”; for, in spite of their size, they were of the same liliaceous family as the onion, chive, shallot, or asparagus. These trees produce ligneous roots which, when cooked, are excellent; from them, by fermentation, a very agreeable liquor is made. They therefore made a good store of the roots. The journey through the wood was long; it lasted the whole day, and so allowed plenty of time for examining the flora and fauna. Top, who took special charge of the fauna, ran through the grass and brushwood, putting up all sorts of game. Herbert and Gideon Spilett killed two kangaroos with bows and arrows, and also an animal which strongly resembled both a hedgehog and an ant-eater. It was like the first because it rolled itself into a ball, and bristled with spines, and the second because it had sharp claws, a long slender snout which terminated in a bird’s beak, and an extendible tongue, covered with little thorns which served to hold the insects. “And when it is in the pot,” asked Pencroft naturally, “what will it be like?” “An excellent piece of beef,” replied Herbert. “We will not ask more from it,” replied the sailor. During this excursion they saw several wild boars, which however, did not offer to attack the little band, and it appeared as if they would not meet with any dangerous beasts; when, in a thick part of the wood, the reporter thought he saw, some paces from him, among the lower branches of a tree, an animal which he took for a bear, and which he very tranquilly began to draw. Happily for Gideon Spilett, the animal in question did not belong to the redoubtable family of the plantigrades. It was only a koala, better known under the name of the sloth, being about the size of a large dog, and having stiff hair of a dirty color, the paws armed with strong claws, which enabled it to climb trees and feed on the leaves. Having identified the animal, which they did not disturb, Gideon Spilett erased “bear” from the title of his sketch, putting koala in its place, and the journey was resumed. At five o’clock in the evening, Cyrus Harding gave the signal to halt. They were now outside the forest, at the beginning of the powerful spurs which supported Mount Franklin towards the west. At a distance of some hundred feet flowed the Red Creek, and consequently plenty of fresh water was within their reach. The camp was soon organized. In less than an hour, on the edge of the forest, among the trees, a hut of branches interlaced with creepers, and pasted over with clay, offered a tolerable shelter. Their geological researches were put off till the next day. Supper was prepared, a good fire blazed before the hut, the roast turned, and at eight o’clock, while one of the settlers watched to keep up the fire, in case any wild beasts should prowl in the neighborhood, the others slept soundly. The next day, the 21st of April, Cyrus Harding accompanied by Herbert, went to look for the soil of ancient formation, on which he had already discovered a specimen of ore. They found the vein above ground, near the source of the creek, at the foot of one of the northeastern spurs. This ore, very rich in iron, enclosed in its fusible veinstone, was perfectly suited to the mode of reduction which the engineer intended to employ; that is, the Catalan method, but simplified, as it is used in Corsica. In fact, the Catalan method, properly so called, requires the construction of kilns and crucibles, in which the ore and the coal, placed in alternate layers, are transformed and reduced, But Cyrus Harding intended to economize these constructions, and wished simply to form, with the ore and the coal, a cubic mass, to the center of which he would direct the wind from his bellows. Doubtless, it was the proceeding employed by Tubalcain, and the first metallurgists of the inhabited world. Now that which had succeeded with the grandson of Adam, and which still yielded good results in countries rich in ore and fuel, could not but succeed with the settlers in Lincoln Island. The coal, as well as the ore, was collected without trouble on the surface of the ground. They first broke the ore into little pieces, and cleansed them with the hand from the impurities which soiled their surface. Then coal and ore were arranged in heaps and in successive layers, as the charcoal-burner does with the wood which he wishes to carbonize. In this way, under the influence of the air projected by the blowing-machine, the coal would be transformed into carbonic acid, then into oxide of carbon, its use being to reduce the oxide of iron, that is to say, to rid it of the oxygen. Thus the engineer proceeded. The bellows of sealskin, furnished at its extremity with a nozzle of clay, which had been previously fabricated in the pottery kiln, was established near the heap of ore. Using the mechanism which consisted of a frame, cords of fiber and counterpoise, he threw into the mass an abundance of air, which by raising the temperature also concurred with the chemical transformation to produce in time pure iron. The operation was difficult. All the patience, all the ingenuity of the settlers was needed; but at last it succeeded, and the result was a lump of iron, reduced to a spongy state, which it was necessary to shingle and fagot, that is to say, to forge so as to expel from it the liquefied veinstone. These amateur smiths had, of course, no hammer; but they were in no worse a situation than the first metallurgist, and therefore did what, no doubt, he had to do. A handle was fixed to the first lump, and was used as a hammer to forge the second on a granite anvil, and thus they obtained a coarse but useful metal. At length, after many trials and much fatigue, on the 25th of April several bars of iron were forged, and transformed into tools, crowbars, pincers, pickaxes, spades, etc., which Pencroft and Neb declared to be real jewels. But the metal was not yet in its most serviceable state, that is, of steel. Now steel is a combination of iron and coal, which is extracted, either from the liquid ore, by taking from it the excess of coal, or from the iron by adding to it the coal which was wanting. The first, obtained by the decarburation of the metal, gives natural or puddled steel; the second, produced by the carburation of the iron, gives steel of cementation. It was the last which Cyrus Harding intended to forge, as he possessed iron in a pure state. He succeeded by heating the metal with powdered coal in a crucible which had previously been manufactured from clay suitable for the purpose. He then worked this steel, which is malleable both when hot or cold, with the hammer. Neb and Pencroft, cleverly directed, made hatchets, which, heated red-hot, and plunged suddenly into cold water, acquired an excellent temper. Other instruments, of course roughly fashioned, were also manufactured; blades for planes, axes, hatchets, pieces of steel to be transformed into saws, chisels; then iron for spades, pickaxes, hammers, nails, etc. At last, on the 5th of May, the metallic period ended, the smiths returned to the Chimneys, and new work would soon authorize them to take a fresh title. About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Jules Verne (1998). The Mysterious Island. Urbana, Illinois: Project Gutenberg. Retrieved October 2022 https://www.gutenberg.org/files/1268/1268-h/1268-h.htm This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at , located at . www.gutenberg.org https://www.gutenberg.org/policy/license.html

The next day, the 17th of April, the sailor’s first words were addressed to Gideon Spilett

In , two captivating figures often emerge: the and the . software development Stubborn Stumper Strategic Solver Picture the Stubborn Stumper, a seasoned developer with grit in his eyes, fervently hammering at the keyboard as if it were an anvil, relentlessly seeking the elusive solution. We'll call him Benjamin. “There's honor in grinding and a sense of achievement in a solution hard-earned,” Benjamin would argue, his belief echoing in the cathedral of code he's built. Now, meet the Strategic Solver, the composed Sherlock of software, armed with an arsenal of tried-and-true methods. She's the embodiment of wisdom - collecting, cataloging, and deploying strategies with surgical precision. We'll call her Laura. she'd whisper as she conjures up the perfect piece of code, as if from thin air. “Elegance lies in efficiency and the well-timed use of the right tool,” So, who's right? Or better yet, is there even a 'right' way when it comes to problem-solving in software development? A Bug on the Horizon: The Different Approaches Benjamin and Laura were both software developers at Phoenix Technologies, a growing tech startup. Then came the day a nasty bug slipped into their codebase, causing random crashes in their software. Benjamin and Laura were assigned to tackle this problem together, their contrasting strategies about to be put to the test. Benjamin’s Battle: The Cost of Stubbornness Benjamin jumped into the fray, his mind brimming with ideas. For him, it was a test of stamina and resilience. But despite his best efforts, the solution eluded him. Yet he soldiered on, becoming more frustrated with each passing hour. Laura’s Strategy: Wisdom Through Proven Techniques Meanwhile, Laura took a different approach. She recognized that this was a complex problem, one that could not be solved simply by brute force. She decided to employ various problem-solving techniques documented by others. A Duck, Divide and Conquer, and Logging: Laura’s Arsenal First, Laura tried the 'Rubber Duck Debugging' technique. When that didn't fully solve the problem, she switched to the 'Divide and Conquer' strategy. Days passed, and Laura was slowly but surely leading her towards the bug by using another method called 'Trace Logging'. The Reveal: Triumph of the Strategic Solver Finally, Laura pinpointed the bug. It was a memory management issue, a tough one to crack, hidden deep within the code. But Laura's systematic approach and the strategic application of different troubleshooting methods had paid off. Lessons Learned: The Power of Strategic Problem-Solving When Laura finally shared her solution, a weary and slightly embarrassed Benjamin conceded that his stubborn approach hadn't been enough. He recognized the power of strategic problem-solving, and, for the first time, acknowledged that he had a lot to learn from Laura's methodical approach. Troubleshooting Techniques Employed by Laura: Rubber Duck Debugging This method involves explaining your problem to an inanimate object, like a rubber duck. It's surprising how often this can lead to insights and solutions. The act of verbalizing your problem can make it more apparent, leading to an 'aha' moment. The Rubber Duck method is based on the principles of cognitive psychology. The act of explaining a problem out loud helps to activate different parts of the brain and can lead to new insights and solutions. Additionally, the process of breaking down a problem into smaller parts and explaining it step-by-step can help to uncover hidden issues and identify potential solutions. Divide and Conquer This strategy is about breaking down the codebase or the problem into smaller pieces and isolating the source of the error. This systematic approach can help navigate complex issues and identify where the problem lies. While the strategy has roots in algorithms, it has a nice application in the troubleshooting toolkit. Dealing with smaller sub-problems can help identify the root cause of the problem more quickly and accurately. It also helps us avoid getting stuck in a particular line of thinking, which can lead to a dead-end in problem-solving. From a psychological perspective, the Divide and Conquer approach helps manage cognitive overload, which is a common problem in complex problem-solving. By breaking down a problem into smaller sub-problems, we can focus our attention on one specific aspect of the problem at a time, reducing the cognitive load and improving problem-solving efficiency. Divide and Conquer works on a few levels by breaking down a complex problem into smaller, more manageable sub-problems where we can then improve problem-solving efficiency and accuracy, avoid getting stuck in a particular line of thinking, all while managing cognitive overload. Trace Logging This technique involves adding logging statements in the code to track the program's execution flow. By reviewing these logs, you can understand how the application is behaving at specific points in time and where things are going wrong. It's particularly useful for identifying elusive bugs that are difficult to reproduce. Trace logging can be implemented in a variety of ways, depending on the programming language and platform being used. Some languages and platforms provide built-in support for trace logging, while others require a bit code to implement it. This can be done with little debug messages like, "got here." However, it is important to note that trace logging can also generate a large amount of data, which can be difficult to analyze and interpret. We must be careful to use this method deliberately and focus on the most relevant areas to avoid getting bogged down in irrelevant details -- and the logs when no longer necessary. remove Embracing Strategy Over Stubbornness In our industry, problems are inevitable. Bugs, crashes, and unexplained behaviors are all part and parcel of a developer's life. But as Benjamin and Laura have demonstrated, the way we tackle these problems can drastically affect our productivity, stress levels, and even our sense of job satisfaction. Benjamin's relentless, headstrong approach may have a heroic ring to it, but it's often the quiet, strategic wisdom of developers like Laura that carry the day. By stepping back from the immediacy of the problem, evaluating the situation, and applying targeted troubleshooting techniques, we can transform problems from daunting obstacles into minor challenges. Ultimately, the most effective problem solvers are those who are willing to learn from others, to leverage proven strategies, and to adapt their approach based on the task at hand. Stubbornness may win battles, but strategy wins wars. When the inevitable tricky bug or complex feature next comes your way, think of Laura with her rubber duck, her divide-and-conquer strategy, and her meticulous logging. Embrace the art of strategic problem solving, and turn your coding challenges into opportunities for growth and learning. As the ancient proverb says, "Give me six hours to chop down a tree and I will spend the first four sharpening the axe." Also published here.

Stubborn vs. Strategic Approaches to Problem-Solving in Software Development

The Story-book of Science by Jean-Henri Fabre, is part of the HackerNoon Books Series. You can jump to any chapter in this book here . THE SUN CHAPTER LIV. THE SUN EARLY in the morning Uncle Paul and his nephews climbed the neighboring hill to see the sunrise. It was still quite dark. The only persons they met in passing through the village were the milkmaid, on her way to town with her butter and milk, and the blacksmith hammering away at the red-hot iron on his anvil, while the glow from the forge illumined the darkness of the road. The Sun Sheltered by a clump of juniper-trees, Paul and the three children await the grand spectacle they have come to the top of the hill to see. In the east the sky is getting lighter, the stars turn pale and go out one by one. Flakes of rosy cloud swim in a brilliant streak of light whence gradually there rises a soft illumination. It reaches the zenith, and the blue of day reappears with all its delicate transparency. This cool morning light, this half-daylight that precedes the rising of the sun, is the aurora or morning twilight. In the meantime a lark, the joy of the fields, takes wing to the highest clouds, like a rocket, and is the first to salute the awakening day. It mounts and mounts, always singing, as if to get in front of the sun; and with its enthusiastic songs it celebrates in the high heavens the glory of the day-bringer. Listen: there is a breath of wind in the foliage, which stirs and rustles; the little birds are waking up and chirping; the ox, already led to work in the fields, stops as if thinking, raises its large eyes full of gentleness, and lows; everything becomes animated, and, in its own language, renders thanks to the Master of all things, who with His powerful hand brings us back the sun. And here it is: a bright thread of light bursts forth, and the tops of the mountains are suddenly illumined. It is the edge of the sun beginning to rise. The earth trembles before the radiant apparition. The shining disc keeps rising: there it is almost whole, now completely so, like a grindstone of red-hot iron. The mist of the morning moderates its glare and allows one to look it in the face; but soon no one could endure its dazzling splendor. In the meantime its rays inundate the plain; a gentle heat succeeds the keen freshness of the night; the mists rise from the depths of the valleys and are dissipated; the dew, gathered on the leaves, becomes warm and evaporates; on all sides there is a resumption of life, of the animation suspended during the night. And all day, pursuing its course from east to west, the sun moves on, flooding the earth with light and heat, ripening the yellow harvest, giving perfume to the flowers, taste to fruit, life to every creature. Then Uncle Paul, in the shade of the juniper-trees, began his talk. “What is the sun? Is it large, is it very far away? That, my children, is what I should now like to teach you. “To measure the distance from one point to another, you know of only one means: that of laying off, as many times as it will go, the unit of length, the meter, from one end to the other of the distance to be measured. But science has methods adapted to the measuring of distances that one cannot travel in person; it tells us what must be done to find the height of a tower or mountain, without going to the top, without even approaching the base. They are methods of the same kind as are employed to calculate the distance that separates us from the sun. The result of the astronomer’s calculations is that we are distant from the sun 38 millions of leagues of 4000 meters each. This distance is equivalent to 3800 times the circumference of the earth. I told you that, to make the tour of the terrestrial globe, a man, a good walker, capable of walking ten leagues a day, would take about three years. He would need, then, nearly twelve thousand years to go from the earth to the sun, supposing that the journey were possible. The longest human life is incomparably too short for a journey of this length ever to be accomplished by one person; and a hundred generations of a hundred years each, succeeding one another on the journey and uniting their efforts, would not even be enough.” “And a locomotive,” asked Jules, “how long would it take to get over that distance?” “Do you remember how fast it goes?” “I saw it myself the day we took the trip with you. If one looks out, the road seems to fly back so fast it frightens you and makes you dizzy.” “The locomotive that drew us went at the rate of about ten leagues an hour. Let us suppose a locomotive that never stops and that goes still faster, or fifteen leagues an hour. Rushing at that speed, the engine would go from one end of France to the other in less than a day; and yet, to cover the distance from the earth to the sun, it would take more than three centuries. For such a journey, the fastest engine ever made by the hand of man is hardly more than a sluggish snail ambitious to make the tour of the world.” “And I who thought, not long ago,” said Emile, “that by climbing to the roof and with the aid of a long reed I could touch the sun!” “To one who trusts to appearances the sun is only a dazzling disc, at the most as large as a grindstone.” “That is what I said yesterday,” observed Jules. “But, as it is so far away, it might well be as large as a millstone.” “In the first place, the sun is not flat like a grindstone; it has, like the earth, the shape of a ball. Furthermore, it is much larger than a grindstone, or even than a millstone. “Objects seem to us small in proportion to their distance from us, until finally they become invisible. A high mountain seen from afar seems only a moderate-sized hill; the cross that surmounts a steeple, seen from below, looks very small despite its very large dimensions. It is the same with the sun: it looks so small only because it is very far off; and as the distance is prodigious, its size must be excessive; if not, instead of looking to us like a dazzling grindstone, it would cease to be visible to us. “You found the terrestrial globe enormous; and, despite my comparisons, your imagination, I am sure, has not been able to picture things properly. How will it be with the sun, which is one million four hundred thousand times as large as the earth! If we suppose the sun hollow like a spherical box, to fill it would take one million four hundred thousand balls the size of the earth. “Let us try another comparison. To fill the measure of capacity called the liter, it takes about 10,000 grains of wheat. It would take, then, 100,000 to fill 10 liters or one decaliter, and 1,400,000 to fill 14 decaliters. Well, suppose in one pile 14 decaliters of wheat, and beside it one solitary grain of wheat. For the respective sizes, this isolated grain represents the earth; the pile of 14 decaliters represents the sun.” “How wrong we were!” Claire exclaimed. “This little shining disc, to which, for fear of exaggeration, we should have hesitated to assign the dimensions of a millwheel, is a globe so big that in comparison with its gigantic size the earth is as nothing.” “Oh, God in heaven!” cried Jules. “Yes, my friend, you may well say, ‘God in heaven,’ for the mind is bewildered at the thought of this inconceivable mass. Say: God in heaven! how great You are, You who out of nothing have created the sun and the earth, and hold them both in the shadow of Your hand! “I have not finished, my dear children. One day, in speaking to you of lightning and thunder, I told you that light moves with excessive rapidity. In fact, to come to us from the sun, to cover the distance that a locomotive at its highest speed would take three hundred years to cover, a ray of light needs only the half of a quarter of an hour, or about eight minutes. Now listen to this. Astronomy teaches us that each star, small as it may appear from here, is itself a sun comparable in size to ours; it tells us that these suns, of which we with the naked eye can perceive only a very small part, are so numerous that it is impossible to count them; it tells us that their distance is so great that, to come to us from the nearest star, light, which travels so fast, as I have just told you, takes nearly four years; to reach us from others that are by no means the most distant it takes whole centuries. After that, if you can, estimate the distance that separates us from those far-off suns; think also of their number and size. But no, do not try: the intellect is overwhelmed by these immensities in which is revealed all the majesty of God’s handiwork. Do not try, it would be in vain; but let arise from your heart the burst of admiration that you cannot suppress, and bless God, whose infinite power has scattered suns through the boundless regions of celestial space.” About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Jean-Henri Fabre (2018). The Story-book of Science. Urbana, Illinois: Project Gutenberg. Retrieved https://www.gutenberg.org/cache/epub/56795/pg56795-images.html This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at www.gutenberg.org , located at https://www.gutenberg.org/policy/license.html.

Uncle Paul and his nephews climbed the neighboring hill to see the sunrise

Naval Warfare.—Mechanical Appliances.—Music

The notes on Sculpture

The Life and Love of the Insect by Jean-Henri Fabre, is part of the HackerNoon Books Series. You can jump to any chapter in this book here . THE SACRED BEETLE: THE MODELLING CHAPTER III. THE SACRED BEETLE: THE MODELLING How does the Scarab obtain the maternal pear? It is certain, to begin with, that this is in no wise shaped by the mechanism of conveyance along the ground: the shape is incompatible with a rolling in every direction, at haphazard. We might accept that for the belly of the gourd; but the neck, the ellipsoid nipple, hollowed into a hatching-chamber! This delicate work could never result from violent, unmeasured jerks. The goldsmith’s jewel is not hammered on the blacksmith’s anvil. Together with other reasons, all good in evidence, already quoted, the pear-shaped outline delivers us, I hope, once and for all, from the antiquated belief that placed the egg inside a roughly-jolted ball. To produce his masterpiece, the sculptor retires to his den. Even so the Sacred Beetle. She shuts herself down in her crypt, to model, in contemplative seclusion, the materials introduced. Two opportunities offer for obtaining the block to be worked. In the one case, the Scarab gathers from the heap, according to the method which we know, a choice block, which is kneaded into a ball on the spot and which is already spherical before it is set in motion. Were it only a question of provisions intended for her own meals, she would never act otherwise. When she thinks the ball of sufficient bulk, if the place do not suit her wherein to dig the burrow, she sets out with her rolling burden, walking at random till she lights upon a favourable spot. During the journey, the ball, without improving upon the perfect sphere which it was at the start, hardens a little on the surface and becomes encrusted with earth and little grains of sand. This earthy rind, picked up on the road, is an authentic sign of a more or less long excursion. The detail is not without importance; it will serve us presently. Less frequently, the spot close to the heap whence the block has been extracted satisfies the insect as suitable for the excavation of the burrow. The soil is free from pebbles and easy to dig. Here, no journey is necessary, nor, therefore, any ball convenient for transit. The soft biscuit of the sheep is gathered and stored as found and enters the workshop a shapeless mass, either in one piece, or, if need be, in different lumps. This case occurs seldom in the natural state, because of the coarseness of the ground, which abounds with broken stones. Sites practicable for easy digging are few and far between and the insect has to roam about, with its burden, to find them. In my voleries, on the other hand, where the earthy layer has been purged with the sieve, it is the usual case. Here the earth is easy to dig at any point; wherefore the mother, working for her laying, is content to lower the nearest morsel underground, without giving it any definite shape. Whether the storing without preliminary ball or conveyance be achieved in the fields or in my voleries, the final result is most striking. One day, I see a shapeless lump disappear into the crypt. The next day, or the day after, I visit the workshop and find the artist face [ ]to face with her work. The uncouth mass of the start, the loose shreds introduced by armfuls have become a pear of perfect accuracy and conscientious finish. 34 The artistic object bears the marks of its method of manufacture. The part that rests upon the bottom of the cavity is crusted over with earthy particles; all the rest is of a glossy polish. Owing to its weight, owing also to the pressure exercised when the Scarab manipulates it, the pear, which is still quite soft, has become soiled with grains of earth on the side that touches the floor of the workshop; on the remainder, which is the larger part, it retains the delicate finish which the insect was able to give it. The inferences to be drawn from these minutely-observed details are obvious: the pear is no turner’s work; it has not been obtained by any sort of rolling on the ground of the spacious studio, for then it would have been soiled with earth all over. Besides, its projecting neck precludes this mode of fabrication. It has not even been turned from one side to the other, as is loudly proclaimed by its unblemished upper surface. The Scarab, therefore, has moulded it where it lies, without turning or shifting it in any way; she has modelled it with little taps of her broad battledores, just as when we saw her model her ball in the daylight. Let us now return to the usual case, in the open. The materials then come from a distance and are introduced into the burrow in the form of a ball covered with soil on every part of its surface. What will the insect do with this sphere which contains the paunch of the future pear ready-made? The answer would present no serious difficulty if, limiting my ambition to the results obtained, I sacrificed the means employed. It would be [ ]enough for me, as I have often done, to capture the mother in her burrow with her ball and carry one and all home, to my animal laboratory, to watch events at first hand. 35 A large glass jar is filled with earth, sifted, moistened and heaped to the desired depth. I place the mother and her beloved pill, which she holds embraced, on the surface of this artificial soil. I stow away the apparatus in a half-light and wait. My patience is not very long tried. Urged by the labour of the ovaries, the insect resumes its interrupted work. In certain cases, I see it, still on the surface, destroying its ball, ripping it up, cutting it to pieces, shredding it. This is not in the least the act of one in despair who, finding herself a captive, breaks the cherished object in her bewilderment. It is an act of wise hygienics. A scrupulous inspection of the morsel gathered in haste, among lawless competitors, is often necessary, for supervision is not always easy on the harvesting-spot itself, in the midst of thieves and robbers. The ball may contain a blend of little Onthophagi, of Aphodians, which have not been noticed in the heat of acquisition. These involuntary intruders, finding themselves very comfortable in the heart of the mass, would themselves make good use of the contemplated pear, much to the detriment of the legitimate consumer. The ball must be purged of this starveling brood. The mother, therefore, destroys it, reduces it to atoms, scrutinizes it. Then, out of the collected remnants, the ball is remade, stripped of its earthy rind. It is dragged underground and becomes an immaculate pear, always excepting the surface touching the soil. Oftener still, the ball is thrust by the mother into the [ ]earth of the jar just as I took it from the burrow, with the wrinkled covering which it acquired in rolling across country during the journey from the place where it was found to the spot where the insect intended to use it. In that case, I find it at the bottom of my jar converted into a pear, itself wrinkled and encrusted with earth and sand over the whole of its surface, thus proving that the pear-shaped outline has not demanded a general recasting of the mass, inside as well as out, but has been obtained by simple pressure and by drawing out the neck. 36 This is how, in the vast majority of cases, things happen in the normal state. Almost all the pears which I dig up in the fields are crusted, unpolished, some more, others less. If we put on one side the inevitable encrustations due to the carting across fields, these blemishes would seem to point to a prolonged rolling in the interior of the subterranean manor. The few which I find perfectly smooth, especially those wonderfully neat specimens furnished by my voleries, dispel this mistake entirely. They show us that, with materials collected near at hand and stored away unshaped, the pear is modelled wholly without rolling; they prove to us that, where the others are concerned, the earthy wrinkles of the rind are not the signs of a rolling manipulation at the bottom of the workshop, but simply the marks of a fairly long journey on the surface of the ground. To be present at the construction of the pear is no easy matter: the sombre artist obstinately refuses to do any work as soon as the light reaches her. She needs absolute darkness for her modelling; and I need light if I would see her at work. It is impossible to unite the two conditions. Let us try, nevertheless; let us seize by fragments the truth which hides itself in its fulness. PLATE III 1. The Sacred Beetle pushing away and overturning a thieving friend who tries to force his assistance upon him. 2. Crypt in which the Beetle shapes a grub’s provision into a pear. The arrangements made are as follows: I once more take the large glass jar. I cover the bottom with a layer of earth a few inches in thickness. To obtain the transparent workshop necessary for my observations, I fix a tripod on the earthy layer and, on this support, a decimetre high, I place a round deal slab of the same diameter as the jar. The glass-walled chamber thus marked out will represent the roomy crypt in which the insect works. In the edge of the deal slab, a hollow is cut, large enough to permit of the passage of the Sacred Beetle and her ball. Lastly, above this screen, I heap a layer of earth as deep as the jar allows. 1 During the operation, a portion of the upper earth falls through the opening and slips down to the lower space in a wide inclined plane. This was a circumstance which I had foreseen and which was indispensable to my plan. By means of this slope, the artist, when she has found the communicating trap-door, will make for the transparent den which I have arranged for her. She will make for it, of course, only provided that she be in perfect darkness. I therefore contrive a cardboard cylinder, closed at the top, and place the glass apparatus inside it. Left standing where it is, the opaque sheath will provide the dusk which the Scarab demands; suddenly raised, it will give the light which I require on my side. Things being thus arranged, I go in search of a mother lately removed from her natural lodging with her ball. A morning is enough to provide me with what I need. I place the mother and her ball on the surface of the upper layer of earth; I cap the apparatus with its cardboard sheath; and I wait. The insect, stubborn at [ ]its work so long as the egg is not deposited, will dig itself a new burrow, dragging its ball with it as it goes; it will pass through the upper layer of earth, which is not sufficiently thick; it will come upon the deal board, an obstacle similar to the broken stones that often bar its passage in the course of its normal excavations; it will investigate the cause of the impediment and, finding the opening, will descend through this trap-door to the lower compartment, which, being free and roomy, will represent to the insect the crypt whence I have just removed it. Thus prophesies my foresight. But all this takes time; and I must wait for the morrow to satisfy my impatient curiosity. 38 The hour has come: let us go and see. The study-door was left open yesterday: the mere sound of the door-handle might stop my distrustful worker. By way of greater precaution, before entering, I put on silent slippers. And——whoosh! The cylinder is removed. Capital! My expectations are fully justified. The Scarab occupies the glazed workshop. I catch her at work, with her broad foot laid on the rough sketch of the pear. But, startled by the sudden light, she remains motionless, as though petrified. This lasts a few seconds. Then she turns her back upon me and awkwardly ascends the inclined plane, to reach the darkling heights of her gallery. I give a glance at the work, take note of its shape, its position and its aspect, and restore darkness with the cardboard sheath. Let us not prolong the indiscretion, if we would renew the test. My sudden, brief visit gives us a first insight into the mysterious work. The ball, at first exactly spherical, now has a stout pad circumscribing a sort of shallow [ ]crater. The work reminds me, in greatly reduced proportions, of certain prehistoric pots, with round bellies, thick lips around the mouth and a neck strangled by a narrow groove. This rude outline of a pear tells us of the insect’s method, a method identical with that of Pleistoscene man ignorant of the potter’s wheel. 39 The plastic ball, girt with a circle at one end, has been hollowed out in a groove, the starting-point of the neck; it has, moreover, been drawn out a little into an obtuse projection. In the centre of this projection, a pressure has been effected, which, causing the matter to fall back over the edges, has produced the crater, with its shapeless lips. Circular enlacement and pressure have sufficed for this first part of the work. Fig. 2.—The Sacred Beetle’s pill dug out cupwise to receive the egg. Towards evening, I pay a fresh sudden visit, amid complete silence. The insect has recovered from its excitement of the morning and gone down again to its workshop. Flooded with light and baffled by the strange events to which my artifices give rise, it at once makes off and takes refuge in the upper storey. The poor mother, persecuted by my illuminations, runs up into the thick of the darkness, but regretfully, with hesitating strides. The work has progressed. The crater has become deeper; the thick lips have disappeared, are thinner, closer together, drawn out into the neck of a pear. The object, however, has not changed its place. Its position, its aspect are exactly as I noted them before. The [ ]side that lay on the ground is still at the bottom, at the same point; the side that faced upwards is still at the top; the crater that lay on my right has been replaced by the neck, still on my right. Whence comes a conclusion completely confirming my previous statements: no rolling; mere pressure, which kneads and moulds. 40 The next day, a third visit. The pear is finished. Its neck, yesterday a yawning sack, is now closed. The egg, therefore, is laid; the work has been carried through and demands only the finishing touches of general polishing, touches upon which the mother, so intent on geometrical perfection, was doubtless engaged at the time when I disturbed her. The most delicate part of the affair escapes my observation. I see quite clearly, in the main, how the hatching-chamber of the egg is obtained: the thick pad surrounding the original crater is thinned and flattened out under the pressure of the feet and lengthened into a sack the mouth of which gradually narrows. Up to this point, the work provides its own explanation. But we have no explanation of the exquisite perfection of the cell wherein the egg is to hatch, when we think of the insect’s rigid tools, the wide, toothed armlets whose jerky awkwardness suggests the spasmodic movements of an automaton. With this clumsy equipment, excellently adapted to coarse work though it be, how does the Scarab obtain the natal dwelling, the oval nest so daintily polished and glazed within? Does the foot, a regular saw, fitted with enormous teeth, begin to rival the painter’s brush in delicacy from the moment when it is inserted through the narrow orifice of the sack? Why not? I have said elsewhere and this is the occasion to repeat it: [ ]the tool does not make the workman. The insect exerts its gifts as a specialist with any kind of tool wherewith it is supplied. It can saw with a plane or plane with a saw, like the model workman of whom Franklin tells us. The same strong-toothed rake with which the Sacred Beetle rips the earth is used by her as a trowel and brush wherewith to glaze the stucco of the chamber in which the grub will be born. 41 In conclusion, one more detail concerning this hatching-chamber. At the extreme end of the neck of the pear, one point is always pretty clearly distinguished: it bristles with stringy fibres, while the rest of the neck is carefully polished. This is the plug with which the mother has closed the narrow opening after placing the egg; and this plug, as its hairy structure shows, has not been subjected to the pressure which, throughout the rest of the work, crams the smallest projecting scrap into the mass and causes it to disappear. Why this arrangement at the extreme pole, a very curious exception, when every elsewhere the pear has received the powerful blows of the insect’s foot? The hind-end of the egg rests against this plug, which, were it pressed down and driven in, would transmit the pressure to the germ and imperil its safety. The mother, aware of the risk, blocks up the hole without ramming the stopper: the air in the hatching-chamber is thus more easily renewed; and the egg escapes the dangerous concussion of the compressing paddle. About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Jean-Henri Fabre (2022). The Life and Love of the Insect. Urbana, Illinois: Project Gutenberg. Retrieved https://www.gutenberg.org/cache/epub/68974/pg68974-images.html This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at www.gutenberg.org , located at https://www.gutenberg.org/policy/license.html .

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