From earliest times the beacon-fire has sent forth messages

Too Long; Didn't Read

From earliest times the beacon-fire has sent forth messages from hilltops or across inaccessible places. In this country, when the Indian was monarch of the vast areas of forest and prairie, he spread news broadcast to roving tribesmen by means of the signal-fire, and he flashed his code by covering and uncovering it. Castaways, whether in fiction or in reality, instinctively turn to the beacon-fire as a mode of attracting a passing ship. On every hand throughout the ages this simple means of communication has been employed; therefore, it is not surprising that mankind has applied his ingenuity to the perfection of signaling by means of light, which has its own peculiar fields and advantages. Of course, wireless telephony and telegraphy will replace light-signaling to some extent, but there are many fields in which the last-named is still supreme. In fact, during the recent war much use was made of light in this manner and devices were developed despite the many other available means of signaling. One of the chief advantages of light as a signal is that it is so easily controlled and directed in a straight line. Wireless waves, for example, are radiated broadcast to be intercepted by the enemy.