The transmission of letters from one point to another always requires time. Even when a letter is dropped into the post office it will not go until the next regular mail. It was long ago seen that occasions frequently arose when it was necessary to send messages quickly. This was especially important in times of war, when each army desired to know immediately the movements of the enemy. This necessity led to various devices for transmitting messages instantaneously. Any form of signaling would be satisfactory if the signals were visible to the eye of the distant observer. The earliest method of signaling was the use of the beacon fire or the sending of messages by light. In the early colonial period in this country, during the anxious times of Indian hostilities, beacon poles were here and there set up and from them large kettles were suspended which held combustible matter. The burning of this material conveyed the intelligence that danger was at hand. One of the earliest beacon poles was erected on Beacon Hill, in Boston, about 1634. A watchman was constantly at the place to give the signal on the approach of danger. That beacon pole was a tall mast, firmly supported, about seventy feet in height. Tree nails were driven into it to enable the watchman to ascend, and near its top an iron crane projected which supported an iron skeleton frame. In this frame was placed a barrel of tar to be fired when the occasion required the signal. This beacon was more than two hundred feet above the sea level, and the light of it, therefore, could be seen for a great distance inland. Many of the early settlements in New England were made upon the tops of hills in order that the people might the more quickly and easily see the approach of Indians and signal the news to other settlements by bonfires. [Illustration: SIGNALING BY BEACON FIRES.] A second method of signaling was by the use of the semaphore. This was invented by Claude Chappe and was adopted by the French Government in 1794. It consists of an upright post, which supports a horizontal bar or arm, which can be put at various angles. In order to carry out this system of signaling, stations must previously be agreed upon and signal officers constantly on duty. If the intelligence was to be conveyed to a considerable distance intermediate stations must be had. The second station received the signal from the first and transmitted it to the third, and so on. This proved to be a very difficult operation and was never extensively used.