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Something I was really happy about accomplishing in 2017 was getting more practically involved with modern AI. I’ve studied a lot of math, which has certainly been fun, but haven’t done any practical projects, and therefore have nothing to show for my efforts. To remedy this, in April, I applied for an with the aim of building skip-gram models for Kenyan speech. I became a finalist in the first round, but failed to win a grant. AI Grant FastText Then, this September, I applied to the international fellowship track of a now-complete class on , taught by Jeremy Howard of . It will be publicly available as a MOOC in the first two weeks or so of January 2018. Over 7 weeks, I learned how to use a set of 8 techniques for building: Practical Deep Learning for Coders, Part 1 v2 fast.ai world-class image classifiers from pre-trained models, sentiment analysis tools by building language models from the data sets under investigation, how to do deep learning on structured data sets, and how to use deep learning to build recommendation engines through collaborative filtering. All this was done through the extremely productive interface known as the Jupyter Notebook, supported by the deep learning library, which is itself supported by PyTorch. fastai So here are the 8 techniques. In each case, I’ll outline the general idea with short snippets of code, and indicate (in parentheses) whether each technique is generally applicable (useful whether you’re doing DL for image recognition and classification, NLP, modeling structured data or collaborative filtering), or more specific to the kind of data you’re trying to apply deep learning to. During the class, the image recognition lessons were done using the Kaggle challenges , , and . fastai Dogs vs. Cats: Kernels Edition Dog Breed Identification Planet: Understanding the Amazon from Space Because this is the Internet, I made my own challenge, which was to clone Dogs vs. Cats, but with spiders and scorpions instead. Spiders vs. Scorpions. I grabbed the data from Google Images, by searching ‘spider’ and ‘desert scorpion’ and downloading about 1500 images or so. I automated this, obviously. I didn’t want to automatically become an expert on esoteric spiders and right-clicking. I cleaned up the data by removing any non-jpg images, any non-image cruft, and images that had no extension. By the time I was done filtering out the junk, I had about 815 images to work with. Each class had 290 in the training set, with 118 spiders and 117 scorpions in the test/validation set. Surprisingly (for me, when I learned this), it works! My model reached about 95% accuracy. [spiders, scorpions] Transfer learning by fine-tuning VGG-16 and ResNext50. (computer vision and image classification) For image classification work, you can get a lot of mileage by fine-tuning, for your specific problem, a neural network architecture that has done well on a more general challenge. An example is the residual network , a 50-layer convolutional neural network. It was trained on the 1000 categories of the ImageNet challenge, and because it performed very well, the features it was able to extract from the image data are general enough to be reused. To get it to work for my problem domain, what I needed to do was replace the last layer, which outputs a 1000-dimensional vector of ImageNet predictions, with a layer which outputs a 2-dimensional vector. The two output classes are specified in the folder called in the code snippet above. For the Spider vs. Scorpion challenge, I had the following: ResNext50 PATH $ ls -lsh data/spiderscorpions/train/128K drwxrwxrwx 1 bmn bmn 128K Jan  3 00:22 scorpions148K drwxrwxrwx 1 bmn bmn 148K Jan  3 00:22 spiders Notice that the two contents of the folder are themselves folders, each containing 290 images. train An example diagram of the fine-tuning procedure is shown here, which retrains a 10-dimensional final layer: Image obtained from here Cyclical Learning Rates (generally applicable) The learning rate is probably . The way it is typically done, in a non-adaptive setting (i.e. not using Adam, AdaDelta or their variants), is by a DL practitioner/researcher running, in parallel, multiple experiments, each with a small delta difference between learning rates. This takes a terribly long time if you have a large dataset and is quite error prone, if you are inexperienced in the ways of . However, in 2015, Leslie N. Smith, of the US Naval Research Laboratory, by starting from a very small value, running a few mini-batches through the network, and tweaking the learning rate while tracking the change to the loss, until the loss starts decreasing. Two blog posts by fellow fast.ai students explaining the cyclical learning rates method are and . the most important hyper-parameter to tune for training deep neural networks building intuition with stochastic matrices found a way to automatically search for the optimal learning rate here here In fastai, you take advantage of learning rate annealing by running on your learner object, and to identify the point which coincides with the optimal learning rate. A screenshot: lr_find() sched.plot() 0.1 seems like a good learning rate An excerpt from the cyclical learning rate paper shows that it performs better, reaching the the highest accuracy, and more than twice as fast as letting the learning rate decay exponentially. Fig. 1: Smith (2017) “ Cyclical learning rates for training neural networks.” Stochastic Gradient Descent with Restarts (generally applicable) Fig. 2: SGD vs. snapshot ensembles ( ) Huang et al., 2017 Another method for speeding up stochastic gradient descent involves gradually decreasing the learning rate as training progresses. What this helps with is noticing when changes to the learning rate coincide with improvements in the loss. As you get closer to the optimal weights, you want to take smaller steps, because if you take large steps you might skip the optimal region of the error surface. If the relationship between the learning rate and loss is unstable, i.e. if a small change to the learning rate results in a large change in the loss, then we’re not in a stable region (image 2 above). Then the strategy becomes to periodically increase the learning rate. The ‘period’ here is a number which determines how many times to increase the learning rate. This is the cyclical learning rate schedule. In fastai, this is set using and params to . In image 2 above, the learning rate is reset 3 times. It usually takes a much longer time to find the optimal loss when using the normal learning rate schedule, where a developer waits until all the epochs are complete before manually trying again with a different learning rate. cycle_len cycle_mult learner.fit Data augmentation (computer vision and image classification — for now) Data augmentation is a simple method for increasing the amount of training and test data you have. For images, this depends on the learning problem at hand, and therefore on the number of symmetries in the images in the dataset. An example is the Spiders vs. Scorpions toy challenge. Many pictures in this dataset could be reflected vertically and still show the animal without weird distortions. This is called . Example: transforms_side_on From top to bottom, notice the different angles, zoom and reflections. Test-time augmentation (computer vision and image classification — for now) We can also use data augmentation at inference time (or test time, hence the name). At inference time, all you’re doing is making predictions. You could do it with the individual images in the test set, but the process becomes more robust if randomly generate a few augmentations of each image in the test set that is accessed. In fastai, 4 random augmentations per test image are used in the predictions, and the average of those predictions is used as the prediction for that image. Replace word vectors with a pretrained recurrent neural network A way to get a world-class sentiment analysis framework, without using word vectors, is to take the entire training data set that you intend to analyze and build a deep recurrent neural network language model from it. Save the model’s encoder when the model has high accuracy and use the embeddings you get from the encoder to build a sentiment analysis model. This works better than the embedding matrices one gets from word vectors because RNNs can keep track of long range dependencies better than word vectors. Back-propagation through time (BPTT) (NLP) The hidden state in a deep recurrent neural network can grow to an unwieldy size if it isn’t reset after back-propagating some time-steps. For example, in a character-level RNN, if you have a million characters, then you also have a million hidden state vectors, each with their history. To adjust the gradients of the neural network, we then need to perform 1 million computations of the chain rule per character, per batch. This will consume too much memory. So, to lower the memory requirements, we set a maximum number of characters to back-propagate to. Since each loop in a recurrent neural network is known as a time-step, the task of limiting the number of layers through which back-propagation retains the history of the hidden state is called back-propagation through time. The value of this number determines the time and memory requirements of the model’s computation, but it improves the model’s ability to handle long sentences or sequences of actions. Entity embedding of categorical variables. (Structured Data and NLP) When doing deep learning on structured data-sets, it helps to distinguish columns that contain continuous data, such as price information in an online store, from columns that contain categorical data, e.g. dates and pick-up locations. One can then convert the one-hot encoding process for these categorical columns into a look-up table that points to an fully-connected embedding layer of a neural network. Your neural network therefore gets an opportunity to learn things about those categorical variables/columns that would have been ignored had the categorical nature of the columns been ignored. It can learn cyclical events, such as which days of the week have the most sales, what happens just before public holidays and just after, for multi-year data-sets. The end-result of this is a very effective method for predicting optimal pricing for products and collaborative filtering. This should be a standard data analysis and prediction method for all companies that have tabular data. Which is all of them. All companies should be using this. This method was applied in the Kaggle competition by Guo and Berkhahn, which got them to third place even if they only used deep learning with minimal feature engineering. They outlined their method in . Rossmann Store Sales this paper Guo, Berkhahn (2016) Fin. The deep learning sub-field of AI is getting easier and easier to get into, as libraries get better. It feels like researchers and practitioners have hill-climbed their way, with bigger and bigger strides, enabled by hard work compiling large data sets and capable GPUs, to the grand achievement of releasing, in the open, a set of tools that promise to upend the course of human history. To my mind, the greatest potential lies in education and medicine, especially rejuvenation biotechnology. Even before we to , with the right policy, insight, motivation and global coordination, we’ll be smarter, richer, and should expect to live much, much longer, healthier lives by the end of this century because of these tools. use deep learning create artificial general intelligence

8 Deep Learning Best Practices I Learned About in 2017

Scientific American Supplement, No. 717, September 28, 1889, by Various, is part of the HackerNoon Books Series. You can jump to any chapter in this book . PRESERVATION OF SPIDERS FOR THE CABINET. here PRESERVATION OF SPIDERS FOR THE CABINET. For several years past, I have devoted a portion of my leisure time to the arrangement of the collection of Arachnidæ of the Natural History Museum of the University of Gand. This collection, which is partially a result of my own captures, is quite a large one, for a university museum, since it comprises more than six hundred European and foreign specimens. Each group of individuals of the small forms and each individual of the large forms is contained in a bottle of alcohol closed with a ground glass stopper, and, whenever possible, the specimens have been spread out and fixed upon strips of glass. The loss of alcohol through evaporation is almost entirely prevented by paraffining the stoppers and tying a piece of bladder over them. Properly labeled, the series has a very satisfactory aspect, and is easily consulted for study. The reader, however, will readily understand how much time and patience such work requires, and can easily imagine how great an amount of space the collection occupies, it being at least twenty times greater than that that would be taken up by a collection of an equal number of insects mounted in the ordinary way on pins and kept in boxes. These inconveniences led me to endeavor to find out whether there was not some way of preserving spiders, properly so called, in a dry state, and without distortion or notable modification of their colors. Experience long ago taught me that pure and simple desiccation, after a more or less prolonged immersion in alcohol, gives passable results only with scorpions, galeodes, phrynes, and mygales, and consequently with arachnides having thick integuments, while it is entirely unsuccessful with most of the spiders. The abdomen of these shrivels, the characteristic colors disappear in great part, and the animals become unrecognizable. Something else was therefore necessary, and I thought of carbolated glycerine. My process, which I have tried only upon the common species of the country— , , , etc., having furnished me with preparations that were generally satisfactory. I think I shall be doing collectors a service by publishing it in the . Tegenaria domestica Epeira cucurbitina Zilla inclinata Naturaliste The specimens should first be deprived of moisture, that is to say, they should be allowed to remain eight or ten days in succession in 50 per cent. alcohol and in pure commercial alcohol. Absolute alcohol is not necessary. After being taken from the alcohol, and allowed to drain, the specimens are immersed in a mixture compound of Pure glycerine 2 volumes, Pure carbolic acid in crystals 1 volume. In this they ought to remain at least a week, but there will be no harm if they are left therein indefinitely, so that the collections of summer may be mounted during winter evenings. What follows is a little more delicate, although very easy. After being removed from the carbolated glycerine, the spiders are placed upon several folds of white filtering paper, and are changed from time to time until the greatest part of the liquid has been absorbed. An insect pin is then passed through the cephalothorax of each individual and is inserted in the support upon which the final desiccation is to take place. This support consists of a piece of sheet cork tacked or glued at the edges to a piece of wood at least one inch in thickness. Upon the cork are placed four or five folds of filtering paper, so that the ventral surface of the pinned spider is in contact with this absorbing surface. For the rest, the legs, palpi, spinnerets, etc., are spread out by means of fine pins, precisely as would be done in the case of coleoptera. The setting board is put for two or three months in a very dry place under cover from dust. The spiders thus treated will scarcely have changed in appearance, the abdomen of the largest Epeiras will have preserved its form, the hairs will in nowise have become agglutinated, and a person would never suspect that glycerine had performed the role. The forms with a large abdomen require a special precaution; it is necessary to pass the mounting pin through a piece of thin cardboard or of gelatine prolonged behind under the abdomen, because the latter is heavy, and the pedicel that connects it with the cephalothorax easily breaks. The specimens are mounted in boxes lined with cork, just as insects are. As there is nothing simpler than to have in one's laboratory three bottles, two of them containing alcohol and the other containing carbolated glycerine, and as it is easy to make setting boards capable of holding from twenty to thirty individuals at once, it will be seen that, with a little practice, the method is scarcely any more complicated than the one daily employed for coleoptera and orthoptera, which latter, too, must pass through alcohol, and be pinned, spread out, and dried. There are but two additional elements, carbolated glycerine and absorbent paper. I do not estimate the time necessary for desiccation as being very long, since the zoologist can occupy himself with other subjects while the specimens are drying. Let us add that the process renders the preservation indefinite, and that destructive insects are not to be feared. Some vertebrates, such as monkeys, that I preserved in the flesh ten years ago, by a nearly identical method, are still intact— F. Plateau, in Le Naturaliste. 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 (2006). Scientific American Supplement, No. 717, September 28, 1889. Urbana, Illinois: Project Gutenberg. Retrieved https://www.gutenberg.org/cache/epub/17755/pg17755-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

PRESERVATION OF SPIDERS FOR THE CABINET

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 SPIDER’S WEB CHAPTER XXVII. THE SPIDER’S WEB THE next day the little chickens were all hatched and doing well. The hen had led them to the courtyard, and, scratching the soil and clucking, she dug up small seeds which the little ones came and took from their mother’s beak. At the slightest approach of danger, the hen called the brood, and all ran to snuggle under her outspread wings. The boldest soon put their heads out, their pretty little yellow heads framed in their mother’s black feathers. The alarm over, the hen began clucking and scratching again, and the little ones went trotting around her once more. Completely reassured, Mother Ambroisine forever renounced her proverb of the spider. In the evening Uncle Paul continued the story of the epeira. “Since it must serve as a support to the silken network, the first thread stretched from one bank to the other must be of exceptional firmness. The epeira begins, therefore, by fixing both ends well; then, going and coming on the thread from one extremity to the other, always spinning, it doubles and trebles the strands and sticks them together in a common cable. A second similar cable is necessary, placed beneath the first in an almost parallel direction. It is between the two that the web must be spun. “For this purpose, from one of the ends of the cable already constructed the epeira lets itself fall perpendicularly, hanging by the thread that escapes from its spinnerets. It reaches a lower branch, fastens the thread firmly to it, and ascends to the communicating bridge by the vertical thread it used for descending. The spider then reaches the other bank, still spinning, but without gluing this new strand of silk to the cable. Arrived at the other side, it lets itself slide on to a branch conveniently placed, and there fastens the end of the thread that it has spun on its way from one bank to the other. This second chief piece of the framework becomes a cable by the addition of new threads. Finally the two parallel cables are made firm at each end by divers threads starting from it in every direction and attaching themselves to the branches. Other threads go out from this point and that, from one cable to the other, leaving between them, in the middle of the construction, a large open space, almost circular, destined for the net. “Thus far the epeira has only constructed the framework of its building, a rough but solid framework; now begins the work of fine precision. The net must he spun. Across the open circular space that the divers threads of the framework leave between them, a first thread is stretched. The epeira stations itself right in the middle of this thread, central point of the web to be constructed. From this center numerous threads must start at equal distances from one another and be fastened to the circumference by the other end. They are called radiating lines. Accordingly the epeira glues a thread to the center and, ascending by the transverse thread already stretched, fixes the end of the line to the circumference. That done, it returns to the center by the line that it has just stretched; there it glues a second thread and immediately regains the circumference, where it fastens the end of the second line a short distance from the first one. Going thus alternately from the center to the circumference and from the circumference to the center by way of the last thread just stretched, the spider fills the circular space with radiating lines so regularly spaced that you would say they were traced with rule and compass by an expert hand. “When the radiating lines are finished, the most delicate work of all is still left for the spider. Each of these lines must be bound by a thread that, starting at the circumference, twists and turns in a spiral line around the center, where it terminates. The epeira starts from the top of the web and, unwinding its thread, stretches it from one radiating line to another, keeping always at an equal distance from the outside thread. By thus circling about, always at the same distance from the preceding thread, the spider ends at the center of the radiating lines. The network is then finished. “Now there must be arranged a little ambuscade from which the epeira can survey its web, a resting-room where it finds shelter from the coolness of the night and the heat of the day. In a little bunch of leaves close together the spider builds itself a silk den, a sort of funnel of close texture. That is its usual abiding place. If the weather is favorable and the passage of game abundant, morning and evening especially, the epeira leaves its den and posts itself, motionless, in the center of the web, to watch events more closely and run to the game quickly enough to prevent its escape. The spider is at its post, in the middle of the network, its eight legs spread out wide. It does not move, pretends to be dead. No hunter on the watch would have such patience. Let us copy its example and await the coming of the game.” The children were disappointed: at the moment when the story became the most interesting, Uncle Paul broke off his narrative. “The epeira has interested me very much, Uncle,” said Jules. “The bridge over the stream, the cobweb with its regular radiating lines, and the thread that twists and turns, getting nearer and nearer to the center, the room for ambush and rest-all that is very astonishing in a creature that does these wonderful things without having to learn how. Catching the game ought to be still more curious.” “Very curious indeed. Therefore, instead of telling you about the hunt, I prefer to show it to you. Yesterday, in crossing the field, I saw an epeira constructing its web between two trees on the little stream where such fine crayfish are caught. Let us get up early in the morning and go and see the chase.” 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.

THE SPIDER’S WEB

Insect Adventures by Jean-Henri Fabre and Louise Hasbrouck Zimm, is part of the HackerNoon Books Series. You can jump to any chapter in this book here . THE GEOMETRY OF THE SPIDER’S WEB CHAPTER XXV. THE GEOMETRY OF THE SPIDER’S WEB [This chapter, one of the most wonderful in Fabre’s books, is included in a simplified form in this volume, on account of its interest to such younger readers as have studied geometry.] WHEN we look at the webs of the Garden Spiders, especially those of the Silky Spider and the Banded Spider, we notice first that the spokes or radii are equally spaced; the angles formed by each consecutive pair are of the same value; and this in spite of their number, which in the webs of the Silky Spider sometimes exceeds forty. We know in what a strange way the Spider weaves her web and divides the area of the web into a large number of equal parts or sectors, a number which is almost always the same in the work of each species of Spider. The Spider darts here and there when laying her spokes as if she had no plan, and this irresponsible way of working produces a beautiful web like the rose-window in a church, a web which no designer could have drawn better with compasses. We shall also notice that, in each sector, the various chords, parts of the angular spiral, are parallel to one another and gradually draw closer together as they near the center. With the two radiating lines that frame them they form obtuse angles on one side and acute angles on the other; and these angles remain constant in the same sector, because the chords are parallel. There is more than this: these same angles, the obtuse as well as the acute, do not alter in value, from one sector to another, as far as the eye can judge. Taken as a whole, therefore, the spiral consists of a series of cross-bars intersecting the several radiating lines obliquely at angles of equal value. By this characteristic we recognize what geometricians have named the “logarithmic spiral.” It is famous in science. The logarithmic spiral describes an endless number of circuits around its pole, to which it constantly draws nearer without ever being able to reach it. We could not see such a line, the whole of it, even with our best philosophical instruments. It exists only in the imagination of scientists. But the Spider knows it, and winds her spiral in the same way, and very accurately at that. Another property of this spiral is that if one in imagination winds a flexible thread around it, then unwinds the thread, keeping it taut the while, its free end will describe a spiral similar at all points to the original. The curve will merely have changed places. Jacques Bernouilli, the professor of mathematics who discovered this magnificent theorem, had engraved on his tomb, as one of his proudest titles to fame, the spiral and its double, made by the unwinding of the thread. Written underneath it was the sentence: Eadem mutata resurgo. “I rise again like unto myself.” It was a splendid flight of fancy which showed his belief in immortality. Now is this logarithmic spiral, with its curious properties, merely an idea of the geometricians? Is it a mere dream, an abstract riddle? No, it is a reality in the service of life, a method of construction often employed by animals in their architecture. The Mollusk never makes its shell without reference to the scientific curve. The first-born of the species knew it and put it into practice; it was as perfect in the dawn of creation as it can be to-day. There are perfect examples of this spiral found in the shells of fossils. To this day, the last representative of an ancient tribe, the Nautilus of the Southern Seas, remains faithful to the old design, and still whirls its spiral logarithmically, as did its ancestors in the earliest ages of the world’s existence. Even in the stagnant waters of our grassy ditches, a tiny Shellfish, no bigger than a duckweed, rolls its shell in the same manner. The common snail-shell is constructed according to logarithmic laws. Where do these creatures pick up this science? We are told that the Mollusk is descended from the Worm. One day the Worm, rendered frisky by the sun, brandished its tail and twisted it into a corkscrew for sheer glee. There and then the plan of the future spiral shell was discovered. This is what is taught quite seriously, in these days, as the very last word in science. But the Spider will have none of this theory. For she is not related to the Worm; and yet she is familiar with the logarithmic spiral and uses it in her web, in a simpler form. The Mollusk has years in which to build her spiral, so she makes it very perfectly. The Spider has only an hour at the most to spread her net, so she makes only a skeleton of the curve; but she knows the same line dear to the Snail. What guides her? Nothing but an inborn skill, whose effects the animal is no more able to control than the flower is able to control the arrangement of its petals and stamens. The Spider practices higher geometry without knowing or caring. The thing works of itself and takes its way from an instinct imposed upon creation at the start. The stone thrown by the hand returns to earth describing a certain curve; the dead leaf torn and wafted away by a breath of wind makes its journey from the tree to the ground with a similar curve. The curve is known to science and is called the “parabola.” The geometricians speculate still more about this curve; they imagine it rolling on an indefinite straight line and ask what course the focus of the curve follows. The answer comes that the focus of the parabola describes a “catenary,” a line whose algebraic symbol is so complicated that a numeral will not express it. The nearest it can get is this terrible sum: The geometricians do not attempt to refer to it by this number; they give it a letter, e. Is this line imaginary? Not at all; you may see the catenary frequently. It is the shape taken by a flexible cord when held at each end and relaxed; it is the line that governs the shape of a sail filled out by the wind. All this answers to the number e. What a quantity of abstruse science for a bit of string! Let us not be surprised. A pellet of shot swinging at the end of a thread, a drop of dew trickling down a straw, a splash of water rippling under the kisses of the air, a mere trifle, after all, becomes tremendously complicated when we wish to examine it with the eye of calculation. We need the club of Hercules to crush a fly. Our methods of mathematical investigation are certainly ingenious; we cannot too much admire the mighty brains that have invented them; but how slow and laborious they seem when compared with the smallest actual things! Shall we never be able to inquire into reality in a simpler fashion? Shall we be intelligent enough some day to do without all these heavy formulæ? Why not? Here we have the magic number e reappearing, written on a Spider’s thread. On a misty morning the sticky threads are laden with tiny drops, and, bending under the burden, have become so many catenaries, so many chains of limpid gems, graceful chaplets arranged in exquisite order and following the curve of a swing. If the sun pierce the mist, the whole lights up with rainbow-colored fires and becomes a dazzling cluster of diamonds. The number e is in its glory. Geometry, that is to say, the science of harmony in space, rules over everything. We find it in the arrangement of the scales of a fir-cone, as in the arrangement of a Spider’s sticky snare; we find it in the spiral of a snail-shell, in the chaplet of a Spider’s thread, as in the orbit of a planet; it is everywhere, as perfect in the world of atoms as in the world of immensities. And this universal geometry tells us of a Universal Geometrician, whose divine compass has measured all things. I prefer that, as an explanation of the logarithmic curve of the Nautilus and the Garden Spiders, to the Worm screwing up the tip of its tail. It may not perhaps be in agreement with some latter-day teaching, but it takes a loftier flight. 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 and Louise Hasbrouck Zimm (2014). Insect Adventures. Urbana, Illinois: Project Gutenberg. Retrieved October https://www.gutenberg.org/cache/epub/45812/pg45812-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 .

THE GEOMETRY OF THE SPIDER’S WEB

Insect Adventures by Jean-Henri Fabre and Louise Hasbrouck Zimm, is part of the HackerNoon Books Series. You can jump to any chapter in this book here . THE BUILDING OF A SPIDER’S WEB CHAPTER XXIV. THE BUILDING OF A SPIDER’S WEB THE smallest garden contains the Garden Spiders, all clever weavers. Let us go every evening, step by step, from one border of tall rosemaries to the next. Should things move too slowly, we will sit down at the foot of the shrubs, where the light falls favorably, and watch with unwearying attention. Let us give ourselves a title, “Inspector of Spiders’ Webs!” There are not many people in that profession, and we shan’t make any money by it; but never mind, we shall learn some very interesting things. The Spiders I watch are young ones, much slenderer than they will be in the late autumn. They work by day, work even in the sun, whereas the old ones weave only at night. Work starts in July, a couple of hours before sunset. The spinstresses of my inclosures then leave their daytime hiding-places, choose their posts and begin to spin, one here, another there. There are many of them; we can choose where we please. Let us stop in front of this one, whom we surprise in the act of laying the foundations of her web. She runs about the rosemary hedge, from the tip of one branch to another, within the limits of some eighteen inches. Gradually, she puts a thread in position, drawing it from her body with the combs attached to her hind-legs. She comes and goes impetuously, as though at random; she goes up, comes down, goes up again, dives down again and each time strengthens the points of contact with threads distributed here and there. The result is a sort of frame. The shapeless structure is what she wishes; it marks out a flat, free, and perpendicular space. This is all that is necessary. A special thread, the foundation of the stronger net which will be built later, is stretched across the area of the other. It can be told from the others by its isolation, its position at a distance from any twig that might interfere with its swaying length. It never fails to have, in the middle, a thick white point, formed of a little silk cushion. The time has come to weave the hunting-snare. The Spider starts from the center, which bears the white signpost, and, running along the cross-thread, hurriedly reaches the circumference, that is to say, the irregular frame inclosing the free space. Still with the same sudden movement, she rushes from the outside to the center; she starts again backwards and forwards, makes for the right, the left, the top, the bottom; she hoists herself up, dives down, climbs up again, runs down and always returns to the central landmark by roads that slant in the most unexpected manner. Each time a radius or spoke is laid, here, there, or elsewhere, in what looks like mad disorder. Any one looking at the finished web, so neat and regular in appearance, would think that the Spider laid the spokes in an orderly fashion, one after the other. She does nothing of the sort, but she knows what she is about, all the same. After setting a few spokes in one direction, the Spider runs across to the other side to draw some in the opposite direction. These sudden changes have a reason; they show us how clever the Spider is in her business. If she began by laying all the spokes on one side, she would pull the web out of shape or even destroy it. She must put some on the other side to balance. She is a past mistress of the secrets of rope-building, without serving an apprenticeship. One would think that this interrupted and apparently disordered labor must result in a confused piece of work. Wrong: the rays are equidistant and form a beautifully regular circle. Their number is a characteristic mark of the different species. The Angular Epeira places twenty-one in her web, the Banded Epeira thirty-two, the Silky Epeira forty-two. These numbers are not absolutely fixed; but the variation is very slight. Now which of us would undertake, offhand, without much preliminary experiment and without measuring-instruments, to divide a circle into a given quantity of sectors or parts of equal width? The Garden Spider, though weighted with a wallet and tottering on threads shaken by the wind, performs the delicate division without stopping to think. She achieves it by a method which seems mad according to our notions of geometry. Out of disorder she brings order. We are amazed at the result obtained. How does this Spider come to succeed with her difficult problem, so strangely managed? I am still asking myself the question. The laying of the radii or spokes is finished. The Spider takes her place in the center, on the little cushion. Stationed on this support, she slowly turns round and round. She is engaged on a delicate piece of work. With an extremely thin thread, she describes from spoke to spoke, starting from the center, a spiral line with very close coils. This is the center of the web. I will call it the “resting-floor.” The thread now becomes thicker. The first could hardly be seen; the second is plainly visible. The Spider shifts her position with great slanting strides, turns a few times, moving farther and farther from the center, fixes her line each time to the spoke which she crosses, and at last comes to a stop at the lower edge of the frame. She has described a spiral with coils of rapidly-increasing width. The average distance between the coils, even in the webs of the young Spiders, is about one third of an inch. This spiral is not a curved line. All curves are banished from the Spiders’ work; nothing is used but the straight line and its combinations. This line forms the cross-bars, or supporting rungs, connecting the spokes, or radii. All this is but a support for the snaring-web. Clinging on the one hand to the radii, on the other to the cross-bars, the Spider covers the same ground as when laying the first spiral, but in the opposite direction: formerly, she moved away from the center; now she moves towards it and with closer and more numerous circles. She starts from the end of the first spiral, near the outside of the web. What follows is hard to observe, for the movements are very quick and jerky, consisting of a series of sudden little rushes, sways, and bends that bewilder the eye. The two hind-legs, the weaving implements, keep going constantly. One draws out the thread from the spinneret, and passes it to the other, which lays it on the radius. As soon as the radius is touched, the thread sticks to it by its own glue. The Spider, without a stop of any kind, turns and turns and turns, drawing nearer to the center and always fixing her thread at each spoke which she crosses. At last, at some distance from the center, on the edge of what I have called the resting-floor, the Spider suddenly ends her spiral. She next eats the little cushion in the center, which is a mat of ends of saved silk. She does this to economize silk, for after she has eaten it the cushion will be turned into silk for the next web she spins. Two Spiders, the Banded and the Silky, sign their work by laying a broad white ribbon in a thick zigzag from the center to the lower edge of the web. Sometimes they put a second band of the same shape, but a little shorter, opposite the first, on the upper part of the web. THE STICKY SNARE The spiral part of the Garden Spider’s web is a wonderful contrivance. The thread that forms it may be seen with the naked eye to be different from that of the framework and the spokes. It glitters in the sun, and looks as though it were knotted. I cannot examine it through the microscope outdoors because the web shakes so, but by passing a sheet of glass under the web and lifting it I can take away a few pieces of thread to study. The microscope now shows me an astounding sight. Those threads, so slender as to be almost invisible, are very closely twisted twine, something like the gold cord of officers’ sword-knots. Moreover, they are hollow. They contain a sticky moisture resembling a strong solution of gum arabic. I can see it trickling from the broken ends. This moisture must ooze through the threads, making them sticky. Indeed, they are sticky. When I lay a straw flat upon them, it adheres at once. We see now that the Garden Spider hunts, not with springs, but with sticky snares that catch everything, down to the dandelion-plume that barely brushes against the web. Nevertheless, the Spider herself is not caught in her own snare. Why? For one thing, she spends most of her time on her resting-floor in the middle of the web, which the spiral does not enter. The resting-floor is not at all sticky, as I find when I pass a straw against it. But sometimes when a victim is caught, perhaps right at the end of the web, the Spider has to rush up quickly to bind it and overcome its attempts to free itself. She seems to be able to walk upon her network perfectly well then. Has she something on her feet which makes them slip over the glue? Has she perhaps oiled them? Oil, you know, is the best thing to prevent surfaces from sticking. I pull out the leg of a live Spider and put it to soak for an hour in disulphide of carbon, which dissolves fat. I wash it carefully with a brush dipped in the same fluid. When the washing is finished, the leg sticks to the spiral of the web! We see now that the Spider varnishes herself with a special sweat so that she can go on any part of her web without difficulty. However, she does not wish to remain on the spiral too long, or the oil might wear away, so most of the time she stays on her safe resting-floor. This spiral thread of the Spider’s is very quick to absorb moisture, as I find out by experiment. For this reason the Garden Spiders, when they weave their webs in the early morning, leave that part of the work unfinished, if the air turns misty. They build the general framework, they lay the spokes, they make the resting-floor, for all these parts are not affected by excess moisture; but they are very careful not to work at the sticky spiral, which, if soaked by the fog, would dissolve into sticky threads and lose its usefulness by being wet. The net that was started will be finished to-morrow, if the weather is right. But on hot days this property of the spiral is a fine thing; it does not dry up, but absorbs all the moisture in the atmosphere and remains, at the most scorching times of day, supple, elastic, and more and more sticky. What bird-catcher could compete with the Garden Spider in the art of laying snares? And all this industry and cunning for the capture of a Moth! Then, too, what a passion the Spider has for production. I calculated that, in one sitting, each time that she remakes her web, the Angular Spider produces some twenty yards of gummy thread. The more skillful Silky Spider produces thirty. Well, during two months, the Angular Spider, my neighbor, renewed her snare nearly every evening. During that time she manufactured something like three quarters of a mile of this tubular thread, rolled into a tight twist and bulging with glue. We cannot but wonder how she ever carries so much in her little body, how she manages to twist her silk into this tube, how she fills it with glue! And how does she first turn out plain threads, then russet foam, for her nest, then black stripes to adorn the nest? I see the results, but I cannot understand the working of her factory. 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 and Louise Hasbrouck Zimm (2014). Insect Adventures. Urbana, Illinois: Project Gutenberg. Retrieved October https://www.gutenberg.org/cache/epub/45812/pg45812-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 .

THE BUILDING OF A SPIDER’S WEB

Insect Adventures by Jean-Henri Fabre and Louise Hasbrouck Zimm, is part of the HackerNoon Books Series. You can jump to any chapter in this book here . THE SPIDER’S TELEGRAPH-WIRE CHAPTER XXI. THE SPIDER’S TELEGRAPH-WIRE OF the six Garden Spiders I have noticed, two only, the Banded and the Silky Spiders, stay constantly in their webs, even under the blinding rays of a fierce sun. The others, as a rule, do not show themselves until nightfall. At some distance from the net they have a rough and ready retreat in the brambles, a hiding-place made of a few leaves held together by stretched threads. It is here that they usually remain in the daytime, motionless and sunk in meditation. But the shrill light that vexes them is the joy of the fields. At such time, the Locust hops more nimbly than ever, more gayly skims the Dragon-fly. Besides, the sticky web, in spite of the rents suffered during the night, is still in fairly good condition. If some giddy-pated insect allow himself to be caught, will the Spider, at the distance whereto she has retired, be unable to take advantage of the windfall? Never fear. She arrives in a flash. How does she know what has happened? Let us explain the matter. It is the vibration of the web which tells her, rather than the sight of the captured object. To prove this, I laid upon several Spiders’ webs a dead Locust. I placed the Locust where the Spider might have plainly seen it. Sometimes the Spider was in her web, and sometimes she was outside, in her hiding-place. In both cases, nothing happened at first. The Spider remained motionless, even when the Locust was at a short distance in front of her. She did not seem to see the game at all. Then, with a long straw, I set the dead insect trembling. That was quite enough. The Banded Spider and the Silky Spider hastened to the central floor, the others, who were in hiding, came down from the branch; all went to the Locust, bound him with tape, treated him, in short, as they would treat a live prey captured under the usual conditions. It took the shaking of the web to decide them to attack. If we look carefully behind the web of any Spider with a daytime hiding-place, we shall see a thread that starts from the center of the web and reaches the place where the Spider lurks. It is joined to the web at the central point only. Its length is usually about twenty-two inches, but the Angular Spider, settled high up in the trees, has shown me some as long as eight or nine feet. “The slanting cord is a telegraph wire.” This slanting line is a foot-bridge by which the Spider hurries to her web when there is something going on there, and then, when her errand is finished, returns to her hut. But that is not all it is. If it were, the foot-bridge would be fastened to the upper end of the web. The journey would then be shorter and the slope less steep. The line starts from the center of the net because that is the place where the spokes meet and therefore where the vibration from any part of the net is best felt. Anything that moves upon the web sets it shaking. All then that is needed is a thread going from this central point to carry to a distance the news of a prey struggling in some part or other of the net. The slanting cord is not only a foot-bridge: it is a signaling-apparatus, a telegraph-wire. In their youth, the Garden Spiders, who are then very wide-awake, know nothing of the art of telegraphy. Only the old Spiders, meditating or dozing in their green tent, are warned from afar, by telegraph, of what takes place on the net. To save herself from keeping a close watch that would be drudgery and to remain alive to events even when resting, with her back turned on the net, the hidden Spider always has her foot upon the telegraph-wire. Here is a true story to prove it. An Angular Spider has spun her web between two laurestine-shrubs, covering a width of nearly a yard. The sun beats upon the snare, which is abandoned long before dawn. The Spider is in her day house, a resort easily discovered by following the telegraph-wire. It is a vaulted chamber of dead leaves, joined together with a few bits of silk. The refuge is deep: the Spider disappears in it entirely, all but her rounded hind-quarters, which bar the entrance. With her front half plunged into the back of her hut, the Spider certainly cannot see her web; she could not even if she had good sight, instead of being half blind as she is. Does she give up hunting during this period of bright sunlight? Not at all. Look again. Wonderful! One of her hind-legs is stretched outside the leafy cabin; and the signaling-thread ends just at the tip of that leg. Whoever has not seen the Spider in this attitude, with her hand, so to speak, on the telegraph-receiver, knows nothing of one of the most curious examples of animal cleverness. Let any game appear upon the scene, and the slumberer, at once aroused by means of the leg receiving the vibrations, hastens up. A Locust whom I myself lay on the web gives her this agreeable shock, and what follows? If she is satisfied with her prey, I am still more satisfied with what I have learned. One word more. The web is often shaken by the wind. The signaling-cord must pass this vibration to the Spider. Nevertheless, she does not leave her hut and remains indifferent to the commotion prevailing in the net. Her line, therefore, is something better than a bell-rope; it is a telephone capable, like our own, of transmitting infinitesimal waves of sound. Clutching her telephone-wire with a toe, the Spider listens with her leg; she can tell the difference between the vibration proceeding from a prisoner and the mere shaking caused by the wind. 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 and Louise Hasbrouck Zimm (2014). Insect Adventures. Urbana, Illinois: Project Gutenberg. Retrieved October https://www.gutenberg.org/cache/epub/45812/pg45812-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 .

THE SPIDER’S TELEGRAPH-WIRE

The Life of the Spider by Jean-Henri Fabre, is part of the HackerNoon Books Series. You can jump to any chapter in this book here . THE GARDEN SPIDERS: THE QUESTION OF PROPERTY CHAPTER XIV: THE GARDEN SPIDERS: THE QUESTION OF PROPERTY A dog has found a bone. He lies in the shade, holding it between his paws, and studies it fondly. It is his sacred property, his chattel. An Epeira has woven her web. Here again is property; and owning a better title than the other. Favoured by chance and assisted by his scent, the Dog has merely had a find; he has neither worked nor paid for it. The Spider is more than a casual owner, she has created what is hers. Its substance issued from her body, its structure from her brain. If ever property was sacrosanct, hers is. Far higher stands the work of the weaver of ideas, who tissues a book, that other Spider’s web, and out of his thought makes something that shall instruct or thrill us. To protect our ‘bone,’ we have the police, invented for the express purpose. To protect the book, we have none but farcical means. Place a few bricks one atop the other; join them with mortar; and the law will defend your wall. Build up in writing an edifice of your thoughts; and it will be open to any one, without serious impediment, to abstract stones from it, even to take the whole, if it suit him. A rabbit-hutch is property; the work of the mind is not. If the animal has eccentric views as regards the possessions of others, we have ours as well. ‘Might always has the best of the argument,’ said La Fontaine, to the great scandal of the peace-lovers. The exigencies of verse, rhyme and rhythm, carried the worthy fabulist further than he intended: he meant to say that, in a fight between mastiffs and in other brute conflicts, the stronger is left master of the bone. He well knew that, as things go, success is no certificate of excellence. Others came, the notorious evil-doers of humanity, who made a law of the savage maxim that might is right. We are the larvae with the changing skins, the ugly caterpillars of a society that is slowly, very slowly, wending its way to the triumph of right over might. When will this sublime metamorphosis be accomplished? To free ourselves from those wild-beast brutalities, must we wait for the ocean-plains of the southern hemisphere to flow to our side, changing the face of continents and renewing the glacial period of the Reindeer and the Mammoth? Perhaps, so slow is moral progress. True, we have the bicycle, the motor-car, the dirigible airship and other marvellous means of breaking our bones; but our morality is not one rung the higher for it all. One would even say that, the farther we proceed in our conquest of matter, the more our morality recedes. The most advanced of our inventions consists in bringing men down with grapeshot and explosives with the swiftness of the reaper mowing the corn. Would we see this might triumphant in all its beauty? Let us spend a few weeks in the Epeira’s company. She is the owner of a web, her work, her most lawful property. The question at once presents itself: Does the Spider possibly recognize her fabric by certain trademarks and distinguish it from that of her fellows? I bring about a change of webs between two neighbouring Banded Epeirae. No sooner is either placed upon the strange net than she makes for the central floor, settles herself head downwards and does not stir from it, satisfied with her neighbour’s web as with her own. Neither by day nor by night does she try to shift her quarters and restore matters to their pristine state. Both Spiders think themselves in their own domain. The two pieces of work are so much alike that I almost expected this. I then decide to effect an exchange of webs between two different species. I move the Banded Epeira to the net of the Silky Epeira and vice versa. The two webs are now dissimilar; the Silky Epeira’s has a limy spiral consisting of closer and more numerous circles. What will the Spiders do, when thus put to the test of the unknown? One would think that, when one of them found meshes too wide for her under her feet, the other meshes too narrow, they would be frightened by this sudden change and decamp in terror. Not at all. Without a sign of perturbation, they remain, plant themselves in the centre and await the coming of the game, as though nothing extraordinary had happened. They do more than this. Days pass and, as long as the unfamiliar web is not wrecked to the extent of being unserviceable, they make no attempt to weave another in their own style. The Spider, therefore, is incapable of recognizing her web. She takes another’s work for hers, even when it is produced by a stranger to her race. We now come to the tragic side of this confusion. Wishing to have subjects for study within my daily reach and to save myself the trouble of casual excursions, I collect different Epeirae whom I find in the course of my walks and establish them on the shrubs in my enclosure. In this way, a rosemary-hedge, sheltered from the wind and facing the sun, is turned into a well-stocked menagerie. I take the Spiders from the paper bags wherein I had put them separately, to carry them, and place them on the leaves, with no further precaution. It is for them to make themselves at home. As a rule, they do not budge all day from the place where I put them: they wait for nightfall before seeking a suitable site whereon to weave a net. Some among them show less patience. A little while ago, they possessed a web, between the reeds of a brook or in the holm-oak copses; and now they have none. They go off in search, to recover their property or seize on some one else’s: it is all the same to them. I come upon a Banded Epeira, newly imported, making for the web of a Silky Epeira who has been my guest for some days now. The owner is at her post, in the centre of the net. She awaits the stranger with seeming impassiveness. Then suddenly they grip each other; and a desperate fight begins. The Silky Epeira is worsted. The other swathes her in bonds, drags her to the non-limy central floor and, in the calmest fashion, eats her. The dead Spider is munched for twenty-four hours and drained to the last drop, when the corpse, a wretched, crumpled ball, is at last flung aside. The web so foully conquered becomes the property of the stranger, who uses it, if it have not suffered too much in the contest. There is here a shadow of an excuse. The two Spiders were of different species; and the struggle for life often leads to these exterminations among such as are not akin. What would happen if the two belonged to the same species? It is easily seen. I cannot rely upon spontaneous invasions, which may be rare under normal conditions, and I myself place a Banded Epeira on her kinswoman’s web. A furious attack is made forthwith. Victory, after hanging for a moment in the balance, is once again decided in the stranger’s favour. The vanquished party, this time a sister, is eaten without the slightest scruple. Her web becomes the property of the victor. There it is, in all its horror, the right of might: to eat one’s like and take away their goods. Man did the same in days of old: he stripped and ate his fellows. We continue to rob one another, both as nations and as individuals; but we no longer eat one another: the custom has grown obsolete since we discovered an acceptable substitute in the mutton-chop. Let us not, however, blacken the Spider beyond her deserts. She does not live by warring on her kith and kin; she does not of her own accord attempt the conquest of another’s property. It needs extraordinary circumstances to rouse her to these villainies. I take her from her web and place her on another’s. From that moment, she knows no distinction between meum and tuum: the thing which the leg touches at once becomes real estate. And the intruder, if she be the stronger, ends by eating the occupier, a radical means of cutting short disputes. Apart from disturbances similar to those provoked by myself, disturbances that are possible in the everlasting conflict of events, the Spider, jealous of her own web, seems to respect the webs of others. She never indulges in brigandage against her fellows except when dispossessed of her net, especially in the daytime, for weaving is never done by day: this work is reserved for the night. When, however, she is deprived of her livelihood and feels herself the stronger, then she attacks her neighbour, rips her open, feeds on her and takes possession of her goods. Let us make allowances and proceed. We will now examine Spiders of more alien habits. The Banded and the Silky Epeira differ greatly in form and colouring. The first has a plump, olive-shaped belly, richly belted with white, bright-yellow and black; the second’s abdomen is flat, of a silky white and pinked into festoons. Judging only by dress and figure, we should not think of closely connecting the two Spiders. But high above shapes tower tendencies, those main characteristics which our methods of classification, so particular about minute details of form, ought to consult more widely than they do. The two dissimilar Spiders have exactly similar ways of living. Both of them prefer to hunt by day and never leave their webs; both sign their work with a zigzag flourish. Their nets are almost identical, so much so that the Banded Epeira uses the Silky Epeira’s web after eating its owner. The Silky Epeira, on her side, when she is the stronger, dispossesses her belted cousin and devours her. Each is at home on the other’s web, when the argument of might triumphant has ended the discussion. Let us next take the case of the Cross Spider, a hairy beast of varying shades of reddish-brown. She has three large white spots upon her back, forming a triple-barred cross. She hunts mostly at night, shuns the sun and lives by day on the adjacent shrubs, in a shady retreat which communicates with the lime-snare by means of a telegraph-wire. Her web is very similar in structure and appearance to those of the two others. What will happen if I procure her the visit of a Banded Epeira? The lady of the triple cross is invaded by day, in the full light of the sun, thanks to my mischievous intermediary. The web is deserted; the proprietress is in her leafy hut. The telegraph-wire performs its office; the Cross Spider hastens down, strides all round her property, beholds the danger and hurriedly returns to her hiding-place, without taking any measures against the intruder. The latter, on her side, does not seem to be enjoying herself. Were she placed on the web of one of her sisters, or even on that of the Silky Epeira, she would have posted herself in the centre, as soon as the struggle had ended in the other’s death. This time there is no struggle, for the web is deserted; nothing prevents her from taking her position in the centre, the chief strategic point; and yet she does not move from the place where I put her. I tickle her gently with the tip of a long straw. When at home, if teased in this way, the Banded Epeira—like the others, for that matter—violently shakes the web to intimidate the aggressor. This time, nothing happens: despite my repeated enticements, the Spider does not stir a limb. It is as though she were numbed with terror. And she has reason to be: the other is watching her from her lofty loop-hole. This is probably not the only cause of her fright. When my straw does induce her to take a few steps, I see her lift her legs with some difficulty. She tugs a bit, drags her tarsi till she almost breaks the supporting threads. It is not the progress of an agile rope-walker; it is the hesitating gait of entangled feet. Perhaps the lime-threads are stickier than in her own web. The glue is of a different quality; and her sandals are not greased to the extent which the new degree of adhesiveness would demand. Anyhow, things remain as they are for long hours on end: the Banded Epeira motionless on the edge of the web; the other lurking in her hut; both apparently most uneasy. At sunset, the lover of darkness plucks up courage. She descends from her green tent and, without troubling about the stranger, goes straight to the centre of the web, where the telegraph-wire brings her. Panic-stricken at this apparition, the Banded Epeira releases herself with a jerk and disappears in the rosemary-thicket. The experiment, though repeatedly renewed with different subjects, gave me no other results. Distrustful of a web dissimilar to her own, if not in structure, at least in stickiness, the bold Banded Epeira shows the white feather and refuses to attack the Cross Spider. The latter, on her side, either does not budge from her day shelter in the foliage, or else rushes back to it, after taking a hurried glance at the stranger. She here awaits the coming of the night. Under favour of the darkness, which gives her fresh courage and activity, she reappears upon the scene and puts the intruder to flight by her mere presence, aided, if need be, by a cuff or two. Injured right is the victor. Morality is satisfied; but let us not congratulate the Spider therefore. If the invader respects the invaded, it is because very serious reasons impel her. First, she would have to contend with an adversary ensconced in a stronghold whose ambushes are unknown to the assailant. Secondly, the web, if conquered, would be inconvenient to use, because of the lime-threads, possessing a different degree of stickiness from those which she knows so well. To risk one’s skin for a thing of doubtful value were twice foolish. The Spider knows this and forbears. But let the Banded Epeira, deprived of her web, come upon that of one of her kind or of the Silky Epeira, who works her gummy twine in the same manner: then discretion is thrown to the winds; the owner is fiercely ripped open and possession taken of the property. Might is right, says the beast; or, rather, it knows no right. The animal world is a rout of appetites, acknowledging no other rein than impotence. Mankind, alone capable of emerging from the slough of the instincts, is bringing equity into being, is creating it slowly as its conception grows clearer. Out of the sacred rushlight, so flickering as yet, but gaining strength from age to age, man will make a flaming torch that will put an end, among us, to the principles of the brutes and, one day, utterly change the face of society. 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 (1999). The Life of the Spider. Urbana, Illinois: Project Gutenberg. Retrieved October https://www.gutenberg.org/cache/epub/1887/pg1887-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 .

THE GARDEN SPIDERS: THE QUESTION OF PROPERTY

THE GARDEN SPIDERS: PAIRING AND HUNTING

The Life of the Spider by Jean-Henri Fabre, is part of the HackerNoon Books Series. You can jump to any chapter in this book here . THE GARDEN SPIDERS: THE TELEGRAPH-WIRE CHAPTER XII: THE GARDEN SPIDERS: THE TELEGRAPH-WIRE Of the six Garden Spiders that form the object of my observations, two only, the Banded and the silky Epeira, remain constantly in their webs, even under the blinding rays of a fierce sun. The others, as a rule, do not show themselves until nightfall. At some distance from the net, they have a rough and ready retreat in the brambles, an ambush made of a few leaves held together by stretched threads. It is here that, for the most part, they remain in the daytime, motionless and sunk in meditation. But the shrill light that vexes them is the joy of the fields. At such times, the Locust hops more nimbly than ever, more gaily skims the Dragon-fly. Besides, the limy web, despite the rents suffered during the night, is still in serviceable condition. If some giddy-pate allow himself to be caught, will the Spider, at the distance whereto she has retired, be unable to take advantage of the windfall? Never fear. She arrives in a flash. How is she apprised? Let us explain the matter. The alarm is given by the vibration of the web, much more than by the sight of the captured object. A very simple experiment will prove this. I lay upon a Banded Epeira’s lime-threads a Locust that second asphyxiated with carbon disulphide. The carcass is placed in front, or behind, or at either side of the Spider, who sits moveless in the centre of the net. If the test is to be applied to a species with a daytime hiding-place amid the foliage, the dead Locust is laid on the web, more or less near the centre, no matter how. In both cases, nothing happens at first. The Epeira remains in her motionless attitude, even when the morsel is at a short distance in front of her. She is indifferent to the presence of the game, does not seem to perceive it, so much so that she ends by wearing out my patience. Then, with a long straw, which enables me to conceal myself slightly, I set the dead insect trembling. That is quite enough. The Banded Epeira and the Silky Epeira hasten to the central floor; the others come down from the branch; all go to the Locust, swathe him with tape, treat him, in short, as they would treat a live prey captured under normal conditions. It took the shaking of the web to decide them to attack. Perhaps the grey colour of the Locust is not sufficiently conspicuous to attract attention by itself. Then let us try red, the brightest colour to our retina and probably also to the Spiders’. None of the game hunted by the Epeirae being clad in scarlet, I make a small bundle out of red wool, a bait of the size of a Locust. I glue it to the web. My stratagem succeeds. As long as the parcel is stationary, the Spider is not roused; but, the moment it trembles, stirred by my straw, she runs up eagerly. There are silly ones who just touch the thing with their legs and, without further enquiries, swathe it in silk after the manner of the usual game. They even go so far as to dig their fangs into the bait, following the rule of the preliminary poisoning. Then and then only the mistake is recognized and the tricked Spider retires and does not come back, unless it be long afterwards, when she flings the cumbersome object out of the web. There are also clever ones. Like the others, these hasten to the red-woollen lure, which my straw insidiously keeps moving; they come from their tent among the leaves as readily as from the centre of the web; they explore it with their palpi and their legs; but, soon perceiving that the thing is valueless, they are careful not to spend their silk on useless bonds. My quivering bait does not deceive them. It is flung out after a brief inspection. Still, the clever ones, like the silly ones, run even from a distance, from their leafy ambush. How do they know? Certainly not by sight. Before recognizing their mistake, they have to hold the object between their legs and even to nibble at it a little. They are extremely short-sighted. At a hand’s-breadth’s distance, the lifeless prey, unable to shake the web, remains unperceived. Besides, in many cases, the hunting takes place in the dense darkness of the night, when sight, even if it were good, would not avail. If the eyes are insufficient guides, even close at hand, how will it be when the prey has to be spied from afar! In that case, an intelligence-apparatus for long-distance work becomes indispensable. We have no difficulty in detecting the apparatus. Let us look attentively behind the web of any Epeira with a daytime hiding-place: we shall see a thread that starts from the centre of the network, ascends in a slanting line outside the plane of the web and ends at the ambush where the Spider lurks all day. Except at the central point, there is no connection between this thread and the rest of the work, no interweaving with the scaffolding-threads. Free of impediment, the line runs straight from the centre of the net to the ambush-tent. Its length averages twenty-two inches. The Angular Epeira, settled high up in the trees, has shown me some as long as eight or nine feet. There is no doubt that this slanting line is a foot-bridge which allows the Spider to repair hurriedly to the web, when summoned by urgent business, and then, when her round is finished, to return to her hut. In fact, it is the road which I see her follow, in going and coming. But is that all? No; for, if the Epeira had no aim in view but a means of rapid transit between her tent and the net, the foot-bridge would be fastened to the upper edge of the web. The journey would be shorter and the slope less steep. Why, moreover, does this line always start in the centre of the sticky network and nowhere else? Because that is the point where the spokes meet and, therefore, the common centre of vibration. Anything that moves upon the web sets it shaking. All then that is needed is a thread issuing from this central point to convey to a distance the news of a prey struggling in some part or other of the net. The slanting cord, extending outside the plane of the web, is more than a foot-bridge: it is, above all, a signalling-apparatus, a telegraph-wire. Let us try experiment. I place a Locust on the network. Caught in the sticky toils, he plunges about. Forthwith, the Spider issues impetuously from her hut, comes down the foot-bridge, makes a rush for the Locust, wraps him up and operates on him according to rule. Soon after, she hoists him, fastened by a line to her spinneret, and drags him to her hiding-place, where a long banquet will be held. So far, nothing new: things happen as usual. I leave the Spider to mind her own affairs for some days, before I interfere with her. I again propose to give her a Locust; but, this time, I first cut the signalling-thread with a touch of the scissors, without shaking any part of the edifice. The game is then laid on the web. Complete success: the entangled insect struggles, sets the net quivering; the Spider, on her side, does not stir, as though heedless of events. The idea might occur to one that, in this business, the Epeira stays motionless in her cabin since she is prevented from hurrying down, because the foot-bridge is broken. Let us undeceive ourselves: for one road open to her there are a hundred, all ready to bring her to the place where her presence is now required. The network is fastened to the branches by a host of lines, all of them very easy to cross. Well, the Epeira embarks upon none of them, but remains moveless and self-absorbed. Why? Because her telegraph, being out of order, no longer tells her of the shaking of the web. The captured prey is too far off for her to see it; she is all unwitting. A good hour passes, with the Locust still kicking, the Spider impassive, myself watching. Nevertheless, in the end, the Epeira wakes up: no longer feeling the signalling-thread, broken by my scissors, as taut as usual under her legs, she comes to look into the state of things. The web is reached, without the least difficulty, by one of the lines of the framework, the first that offers. The Locust is then perceived and forthwith enswathed, after which the signalling-thread is remade, taking the place of the one which I have broken. Along this road the Spider goes home, dragging her prey behind her. My neighbour, the mighty Angular Epeira, with her telegraph-wire nine feet long, has even better things in store for me. One morning, I find her web, which is now deserted, almost intact, a proof that the night’s hunting has not been good. The animal must be hungry. With a piece of game for a bait, I hope to bring her down from her lofty retreat. I entangle in the web a rare morsel, a Dragon-fly, who struggles desperately and sets the whole net a-shaking. The other, up above, leaves her lurking-place amid the cypress-foliage, strides swiftly down along her telegraph-wire, comes to the Dragon-fly, trusses her and at once climbs home again by the same road, with her prize dangling at her heels by a thread. The final sacrifice will take place in the quiet of the leafy sanctuary. A few days later, I renew my experiment under the same conditions, but, this time, I first cut the signalling-thread. In vain I select a large Dragon-fly, a very restless prisoner; in vain I exert my patience: the Spider does not come down all day. Her telegraph being broken, she receives no notice of what is happening nine feet below. The entangled morsel remains where it lies, not despised, but unknown. At nightfall, the Epeira leaves her cabin, passes over the ruins of her web, finds the Dragon-fly and eats her on the spot, after which the net is renewed. One of the Epeirae whom I have had the opportunity of examining simplifies the system, while retaining the essential mechanism of a transmission-thread. This is the Crater Epeira (Epeira cratera, WALCK.), a species seen in spring, at which time she indulges especially in the chase of the Domestic Bee, upon the flowering rosemaries. At the leafy end of a branch, she builds a sort of silken shell, the shape and size of an acorn-cup. This is where she sits, with her paunch contained in the round cavity and her forelegs resting on the ledge, ready to leap. The lazy creature loves this position and rarely stations herself head downwards on the web, as do the others. Cosily ensconced in the hollow of her cup, she awaits the approaching game. Her web, which is vertical, as is the rule among the Epeirae, is of a fair size and always very near the bowl wherein the Spider takes her ease. Moreover, it touches the bowl by means of an angular extension; and the angle always contains one spoke which the Epeira, seated, so to speak, in her crater, has constantly under her legs. This spoke, springing from the common focus of the vibrations from all parts of the network, is eminently fitted to keep the Spider informed of whatsoever happens. It has a double office: it forms part of the Catherine-wheel supporting the lime-threads and it warns the Epeira by its vibrations. A special thread is here superfluous. The other snarers, on the contrary, who occupy a distant retreat by day, cannot do without a private wire that keeps them in permanent communication with the deserted web. All of them have one, in point of fact, but only when age comes, age prone to rest and to long slumbers. In their youth, the Epeirae, who are then very wide-awake, know nothing of the art of telegraphy. Besides, their web, a short-lived work whereof hardly a trace remains on the morrow, does not allow of this kind of industry. It is no use going to the expense of a signalling-apparatus for a ruined snare wherein nothing can now be caught. Only the old Spiders, meditating or dozing in their green tent, are warned from afar, by telegraph, of what takes place on the web. To save herself from keeping a close watch that would degenerate into drudgery and to remain alive to events even when resting, with her back turned on the net, the ambushed Spider always has her foot upon the telegraph-wire. Of my observations on this subject, let me relate the following, which will be sufficient for our purpose. An Angular Epeira, with a remarkably fine belly, has spun her web between two laurestine-shrubs, covering a width of nearly a yard. The sun beats upon the snare, which is abandoned long before dawn. The Spider is in her day manor, a resort easily discovered by following the telegraph-wire. It is a vaulted chamber of dead leaves, joined together with a few bits of silk. The refuge is deep: the Spider disappears in it entirely, all but her rounded hind-quarters, which bar the entrance to the donjon. With her front half plunged into the back of her hut, the Epeira certainly cannot see her web. Even if she had good sight, instead of being purblind, her position could not possibly allow her to keep the prey in view. Does she give up hunting during this period, of bright sunlight? Not at all. Look again. Wonderful! One of her hind-legs is stretched outside the leafy cabin; and the signalling-thread ends just at the tip of that leg. Whoso has not seen the Epeira in this attitude, with her hand, so to speak, on the telegraph-receiver, knows nothing of one of the most curious instances of animal cleverness. Let any game appear upon the scene; and the slumberer, forthwith aroused by means of the leg receiving the vibrations, hastens up. A Locust whom I myself lay on the web procures her this agreeable shock and what follows. If she is satisfied with her bag, I am still more satisfied with what I have learnt. The occasion is too good not to find out, under better conditions as regards approach, what the inhabitant of the cypress-trees has already shown me. The next morning, I cut the telegraph-wire, this time as long as one’s arm and held, like yesterday, by one of the hind-legs stretched outside the cabin. I then place on the web a double prey, a Dragon-fly and a Locust. The latter kicks out with his long, spurred shanks; the other flutters her wings. The web is tossed about to such an extent that a number of leaves, just beside the Epeira’s nest, move, shaken by the threads of the framework affixed to them. And this vibration, though so close at hand, does not rouse the Spider in the least, does not make her even turn round to enquire what is going on. The moment that her signalling-thread ceases to work, she knows nothing of passing events. All day long, she remains without stirring. In the evening, at eight o’clock, she sallies forth to weave the new web and at last finds the rich windfall whereof she was hitherto unaware. One word more. The web is often shaken by the wind. The different parts of the framework, tossed and teased by the eddying air-currents, cannot fail to transmit their vibration to the signalling-thread. Nevertheless, the Spider does not quit her hut and remains indifferent to the commotion prevailing in the net. Her line, therefore, is something better than a bell-rope that pulls and communicates the impulse given: it is a telephone capable, like our own, of transmitting infinitesimal waves of sound. Clutching her telephone-wire with a toe, the Spider listens with her leg; she perceives the innermost vibrations; she distinguishes between the vibration proceeding from a prisoner and the mere shaking caused by the wind. 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 (1999). The Life of the Spider. Urbana, Illinois: Project Gutenberg. Retrieved October https://www.gutenberg.org/cache/epub/1887/pg1887-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 .

THE GARDEN SPIDERS: THE TELEGRAPH-WIRE

The Life of the Spider by Jean-Henri Fabre, is part of the HackerNoon Books Series. You can jump to any chapter in this book here . THE GARDEN SPIDERS: THE LIME-SNARE CHAPTER XI: THE GARDEN SPIDERS: THE LIME-SNARE The spiral network of the Epeirae possesses contrivances of fearsome cunning. Let us give our attention by preference to that of the Banded Epeira or that of the Silky Epeira, both of which can be observed at early morning in all their freshness. The thread that forms them is seen with the naked eye to differ from that of the framework and the spokes. It glitters in the sun, looks as though it were knotted and gives the impression of a chaplet of atoms. To examine it through the lens on the web itself is scarcely feasible, because of the shaking of the fabric, which trembles at the least breath. By passing a sheet of glass under the web and lifting it, I take away a few pieces of thread to study, pieces that remain fixed to the glass in parallel lines. Lens and microscope can now play their part. The sight is perfectly astounding. Those threads, on the borderland between the visible and the invisible, are very closely twisted twine, similar to the gold cord of our officers’ sword-knots. Moreover, they are hollow. The infinitely slender is a tube, a channel full of a viscous moisture resembling a strong solution of gum arabic. I can see a diaphanous trail of this moisture trickling through the broken ends. Under the pressure of the thin glass slide that covers them on the stage of the microscope, the twists lengthen out, become crinkled ribbons, traversed from end to end, through the middle, by a dark streak, which is the empty container. The fluid contents must ooze slowly through the side of those tubular threads, rolled into twisted strings, and thus render the network sticky. It is sticky, in fact, and in such a way as to provoke surprise. I bring a fine straw flat down upon three or four rungs of a sector. However gentle the contact, adhesion is at once established. When I lift the straw, the threads come with it and stretch to twice or three times their length, like a thread of India-rubber. At last, when over-taut, they loosen without breaking and resume their original form. They lengthen by unrolling their twist, they shorten by rolling it again; lastly, they become adhesive by taking the glaze of the gummy moisture wherewith they are filled. In short, the spiral thread is a capillary tube finer than any that our physics will ever know. It is rolled into a twist so as to possess an elasticity that allows it, without breaking, to yield to the tugs of the captured prey; it holds a supply of sticky matter in reserve in its tube, so as to renew the adhesive properties of the surface by incessant exudation, as they become impaired by exposure to the air. It is simply marvellous. The Epeira hunts not with springs, but with lime-snares. And such lime-snares! Everything is caught in them, down to the dandelion-plume that barely brushes against them. Nevertheless, the Epeira, who is in constant touch with her web, is not caught in them. Why? Let us first of all remember that the Spider has contrived for herself, in the middle of her trap, a floor in whose construction the sticky spiral thread plays no part. We saw how this thread stops suddenly at some distance from the centre. There is here, covering a space which, in the larger webs, is about equal to the palm of one’s hand, a fabric formed of spokes and of the commencement of the auxiliary spiral, a neutral fabric in which the exploring straw finds no adhesiveness anywhere. Here, on this central resting-floor, and here only, the Epeira takes her stand, waiting whole days for the arrival of the game. However close, however prolonged her contact with this portion of the web, she runs no risk of sticking to it, because the gummy coating is lacking, as is the twisted and tubular structure, throughout the length of the spokes and throughout the extent of the auxiliary spiral. These pieces, together with the rest of the framework, are made of plain, straight, solid thread. But, when a victim is caught, sometimes right at the edge of the web, the Spider has to rush up quickly, to bind it and overcome its attempts to free itself. She is walking then upon her network; and I do not find that she suffers the least inconvenience. The lime-threads are not even lifted by the movements of her legs. In my boyhood, when a troop of us would go, on Thursdays, to try and catch a Goldfinch in the hemp-fields, we used, before covering the twigs with glue, to grease our fingers with a few drops of oil, lest we should get them caught in the sticky matter. Does the Epeira know the secret of fatty substances? Let us try. I rub my exploring straw with slightly oiled paper. When applied to the spiral thread of the web, it now no longer sticks to it. The principle is discovered. I pull out the leg of a live Epeira. Brought just as it is into contact with the lime-threads, it does not stick to them any more than to the neutral cords, whether spokes or parts of the framework. We were entitled to expect this, judging by the Spider’s general immunity. But here is something that wholly alters the result. I put the leg to soak for a quarter of an hour in disulphide of carbon, the best solvent of fatty matters. I wash it carefully with a brush dipped in the same fluid. When this washing is finished, the leg sticks to the snaring-thread quite easily and adheres to it just as well as anything else would, the unoiled straw, for instance. Did I guess aright when I judged that it was a fatty substance that preserved the Epeira from the snares of her sticky Catherine-wheel? The action of the carbon disulphide seems to say yes. Besides, there is no reason why a substance of this kind, which plays so frequent a part in animal economy, should not coat the Spider very slightly by the mere act of perspiration. We used to rub our fingers with a little oil before handling the twigs in which the Goldfinch was to be caught; even so the Epeira varnishes herself with a special sweat, to operate on any part of her web without fear of the lime-threads. However, an unduly protracted stay on the sticky threads would have its drawbacks. In the long run, continual contact with those threads might produce a certain adhesion and inconvenience the Spider, who must preserve all her agility in order to rush upon the prey before it can release itself. For this reason, gummy threads are never used in building the post of interminable waiting. It is only on her resting-floor that the Epeira sits, motionless and with her eight legs outspread, ready to mark the least quiver in the net. It is here, again, that she takes her meals, often long-drawn-out, when the joint is a substantial one; it is hither that, after trussing and nibbling it, she drags her prey at the end of a thread, to consume it at her ease on a non-viscous mat. As a hunting-post and refectory, the Epeira has contrived a central space, free from glue. As for the glue itself, it is hardly possible to study its chemical properties, because the quantity is so slight. The microscope shows it trickling from the broken threads in the form of a transparent and more or less granular streak. The following experiment will tell us more about it. With a sheet of glass passed across the web, I gather a series of lime-threads which remain fixed in parallel lines. I cover this sheet with a bell-jar standing in a depth of water. Soon, in this atmosphere saturated with humidity, the threads become enveloped in a watery sheath, which gradually increases and begins to flow. The twisted shape has by this time disappeared; and the channel of the thread reveals a chaplet of translucent orbs, that is to say, a series of extremely fine drops. In twenty-four hours, the threads have lost their contents and are reduced to almost invisible streaks. If I then lay a drop of water on the glass, I get a sticky solution, similar to that which a particle of gum arabic might yield. The conclusion is evident: the Epeira’s glue is a substance that absorbs moisture freely. In an atmosphere with a high degree of humidity, it becomes saturated and percolates by sweating through the side of the tubular threads. These data explain certain facts relating to the work of the net. The full-grown Banded and Silky Epeirae weave at very early hours, long before dawn. Should the air turn misty, they sometimes leave that part of the task unfinished: they build the general framework, they lay the spokes, they even draw the auxiliary spiral, for all these parts are unaffected by excess of moisture; but they are very careful not to work at the lime-threads, which, if soaked by the fog, would dissolve into sticky shreds and lose their efficacy by being wetted. The net that was started will be finished to-morrow, if the atmosphere be favourable. While the highly-absorbent character of the snaring-thread has its drawbacks, it also has compensating advantages. Both Epeirae, when hunting by day, affect those hot places, exposed to the fierce rays of the sun, wherein the Crickets delight. In the torrid heats of the dog-days, therefore, the lime-threads, but for special provisions, would be liable to dry up, to shrivel into stiff and lifeless filaments. But the very opposite happens. At the most scorching times of the day, they continue supple, elastic and more and more adhesive. How is this brought about? By their very powers of absorption. The moisture of which the air is never deprived penetrates them slowly; it dilutes the thick contents of their tubes to the requisite degree and causes it to ooze through, as and when the earlier stickiness decreases. What bird-catcher could vie with the Garden Spider in the art of laying lime-snares? And all this industry and cunning for the capture of a Moth! Then, too, what a passion for production! Knowing the diameter of the orb and the number of coils, we can easily calculate the total length of the sticky spiral. We find that, in one sitting, each time that she remakes her web, the Angular Epeira produces some twenty yards of gummy thread. The more skilful Silky Epeira produces thirty. Well, during two months, the Angular Epeira, my neighbour, renewed her snare nearly every evening. During that period, she manufactured something like three-quarters of a mile of this tubular thread, rolled into a tight twist and bulging with glue. I should like an anatomist endowed with better implements than mine and with less tired eyesight to explain to us the work of the marvellous rope-yard. How is the silky matter moulded into a capillary tube? How is this tube filled with glue and tightly twisted? And how does this same wire-mill also turn out plain threads, wrought first into a framework and then into muslin and satin; next, a russet foam, such as fills the wallet of the Banded Epeira; next, the black stripes stretched in meridian curves on that same wallet? What a number of products to come from that curious factory, a Spider’s belly! I behold the results, but fail to understand the working of the machine. I leave the problem to the masters of the microtome and the scalpel. 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 (1999). The Life of the Spider. Urbana, Illinois: Project Gutenberg. Retrieved October https://www.gutenberg.org/cache/epub/1887/pg1887-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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