SIGNALING.

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.

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.

A third and successful form of signaling was by the motion of flags. During our Civil War the army made much use of military signals. The system was devised by Major Myer and was continued through the war, not only in the army but on naval vessels. When the stations were less than five miles apart signaling was considered to be at very short range. Messages have been sent ten miles by means of a pocket handkerchief attached to a twelve-foot rod. With the regular flags and staffs used by the signal corps during the war, signals were often read twenty-five miles away, and it is said that single words have been read at a distance of forty miles.

In the early spring of 1863 General Peck was in command of the Union forces at Suffolk, Virginia. He had under him about ten thousand men and had thoroughly fortified the place by a connected system of forts, redoubts, and breast-works. His outmost signal station was placed on an elevated plateau across the Nansemond River. This station was made by sawing off the top of a tall pine tree and placing thereon a small platform surrounded by a railing. The signal officer would tie his horse at the foot of the tree and mount to the platform by a rope ladder.

Early one morning in March, this signal officer suddenly observed the head of a column of troops emerging from the woods in the rear. This was the advance guard of two Confederate corps under General Longstreet. Instantly he caught up his signal flag and as quickly as possible signaled to the town the approach of the enemy. Picking up his signal book he hurried down the ladder, mounted his horse and galloped away. Before he could reach his saddle, however, the Confederates were within rifle range and fired at him. They did not succeed in hitting him and he escaped safely to his friends.

The signal had been seen and was quickly repeated to all parts of the fortified town. The drums instantly beat the long roll and, within five minutes from the time his signal was given, and before General Longstreet could swing out his light battery and open fire, the entire Federal force was under arms and the artillery in the nearest battery had opened a raking fire. The briskness of this fire from the Federal battery soon obliged Longstreet to withdraw his forces to the cover of the woods. Had it not been for the promptness of the signal officer it is possible that the town might have been captured.

A notable use of this system of army signals occurred in the campaign of General Miles against the Apaches in New Mexico and Arizona in 1886. He established a system of thirteen signal stations in that country, over which, during a period of four months, more than eighteen hundred messages were sent. The savages were surprised and confounded by the way intelligence of their movements became known hundreds of miles distant.

As early as 1861 Moses G. Farmer introduced a successful method of signaling which afterward was employed by the officers of the United States Coast Survey on Lake Superior. This system was by means of mirrors which were able to reflect the sunlight between stations ninety miles apart. This method is called the heliographic system. The French have used it among the islands of the Indian Ocean where the stations are on mountain peaks sometimes 135 miles apart. Even this long-range signaling has been surpassed by our own Signal Corps, which has succeeded in sending messages by our method from Mount Uncompahgre in Colorado to Mount Ellen in Utah, a distance of 183 miles. During the siege of Paris, messages by the use of the calcium light, concentrated and directed by lenses, were sent from one point to another.

A very unique form of signaling was employed by New York State at the opening of the Erie Canal, in 1825. The cannon, which had been captured by Commodore Perry at the time of his famous victory on Lake Erie, were placed at intervals along the line of the canal. When the first canal boat started from Buffalo, the first cannon was fired. When the sound was heard at the second cannon, that was discharged; and so on, the entire length of the canal. Two hours after the start at Buffalo the news had reached New York.

All these various methods of communication at long range have proved more or less objectionable and unsatisfactory. It was natural, therefore, that as soon as it was known that electricity could be conducted by wires from one place to another, experiments should be begun in the hope of finding some possible means of conveying intelligence by it. Perhaps the earliest suggestion was in a letter published in The Scots Magazine, of February, 1753. The letter was signed "C. M.", which probably meant Charles Morrison, a young Scotch surgeon. He proposed to use as many insulated conductors as there were letters in the alphabet. Each wire was to represent one letter only, and the message would be sent by charging the several wires in succession so that the operator in receiving it would be obliged to notice the order of movement among the wires. From that simple beginning inventors proceeded to suggest first one thing and then another, but they found so many difficulties that it seemed impossible to overcome them all.