MILITARY TELEGRAPH. The electric telegraph for the transmission of signals came into prac tical use about 1835. Its history and develop ment will be found discussed in the article ELE GRAPH. Beyond saying that the Morse system makes use of a code of three elements. dot, dash, and space, as shown above, it is necessary here to concern ourselves merely with strictly mili tary. lines. With the invention and general use of the telephone came its application to warfare, and this instrument, too, has been specially adapted for this purpose. Military lines for telegraph or telephone field service are generally called 'dying lines.' They are strung on light poles called 'lances,' 24!, inches in diameter and 17 feet long, placed 2 feet in the ground, and about 40 per mile are necessary. Instruments and material are transported by wagons designed for the purpose to accompany the army in the field. These constitute the field telegraph train. For quick work at the front the wire is on reels, carried either on a man's back or on a light cart. The wire is light, strong, and pliable, generally a steel core with copper sheathing, and for the lighter lines is not even insulated. By the use of high frequency currents this bare wire, rapidly reeled MT on the ground, constitutes the conductm for the special 'vibrator' forms of telegraph and telephone instruments now used by the United States Signal Corps.
The special apparatus used by the Signal Corps exhibits many modifications from the accepted commercial practice. One of the most important of the instruments used is the 'buzzer,' which is constructed in forms suitable for regular service or for the field. It consists of a telephone re ceiver and transmitter, a vibrator and induction coil, condenser, telegraph key and switches, and four cells of dry battery. This instrument is used for connecting with rapidly constructed field lines or for working a regular wire under adverse conditions. The Signal Corps has also a special pattern of service telephone, which is constructed so as to withstand rough usage in transit. The telephone is also supplied in a portable form for field use, while for special use on telegraph lines there is an instrument known as the Russell cut in telephone, which is very portable and can be used in the field with great facility.
With the telephone is a special form of cart constructed of bicycle tubing and 30 inch bicycle wheels with heavy cushion rubber tires. The cart is filled with an auto matic spooling device for reeling up the out post cable and carries five reels of cable and one reel knapsack for use in places where the cart cannot penetrate owing to underbrush, etc. As
the extreme width of the cart, measured at the wheels, is only 26 inches, it can follow any ordi nary path through the underbrush. The weight of the cart complete with spooling device, but without reels, is only 53 pounds; when loaded with reels and reel knapsack the total weight is 157 pounds. The cart is well balanced upon its axle by a device which permits the point of sup port to be changed to balance the cart as the distribution of weight is changed by the cable being run out. In connection with the reel cart a telephone kit is used, and by attaching the double connector of the kit to one on the frame of the cart the telephone is kept in circuit and conversation can be kept up with the home sta tion. The cart with its load can be easily drawn by one man, and by its use it is possible to con nect outposts with the main guard or brigade with regimental headquarters, or brigade with division headquarters, in a few minutes of time.
Signal balloons now form a part of the equip ment of all armies. In the United States service they are operated by the Signal Corps. Several successful ascents were made during the Santi ago campaign of the Spanish-Arterican War of IS98. For reconnoitring purposes balloons are recognized as a military necessity. Information is transmitted from the captive balloon by tele graph or telephone, the wire being reeled off during the ascent. From balloons photographs of the enemy's country, defenses, and communica tions may also be taken by the use of telephoto lenses. Balloons for military reconnaissance should be of at least 18,000 cubic feet capacity. Gas for inflation is generally carried compressed in steel cylinders. See AERONAUTICS.
Wireless telegraphy is now an important sub ject of experiment for purposes of military signaling. The Signal Corps of the United States Army has perfected its own system and has in successful operation stations in San Francisco Ifarbor and elsewhere. See WIRELESS TELEGRAPH Y. Consult: Myer, A Manual of Signals (Washington, Government Printing Of fice, 1S79) : Instructions for Using the Helio graph of the Signal Corps, U. S. Army (ib., 1S94) ; Instruction for Signaling, United States Navy, I898 (ib., 1898). See SIGNALS, MARINE; ARMY ORGANIZATION.