The South African War was followed in the British army by a flowering and expanding period in both organization and training, such as it had not before experienced in times of peace. Signalling shared to the full in this development. Wireless telegraph units were added to the army, principally for communication with cav alry formations. Message carrying became recognized as the ally and not the rival of telegraphy in the field, and despatch riders on horse and motor cycle were included in the signal organization; their role was to carry the longer and less pressing messages and so to leave the telegraph free to deal immediately with short and urgent reports and orders. The intercommunication problem was thus seen as a whole, and this inclusion of despatch riding in the signal organization is one of the points which most distinguished the British from the Continental systems. The "telegraph" units of the South African War, which dealt only in line telegraphy, gave place to "signal" units employing in co-operation line teleg raphy, visual telegraphy and despatch riding. And as the British army was during this period definitely organized into divisions and brigades, so each formation had its own signal unit allotted to it for peace and war.
During these years the signal office organization came to be recognized, whereby at each important headquarters in the field the signal unit establishes a signal office, controlling all the avail able means of communications. Here the line telegraph operators work and the despatch riders wait their call, while the visual and wireless stations are as close outside. as they can be placed. All outgoing messages from the headquarters are taken over at the signal office and there handed to the appropriate operator or despatch rider, and from there all incoming messages are dis tributed.
The British signal units were found from the Royal Engineers. It remained for the United States to go a step further and to form a separate signal corps ; a notable organization which did not take long to make its mark in the world of science. In considering the policies which led the one country to retain signalling as a branch of military engineering and the other to form a specialist corps, it must be remembered that all telegraphic communication in Great Britain is a Government monopoly vested in the postmaster general, so that the army's attention is confined to the purely military problem of communication in the field. The United States had no such federal organization, and their signal corps could and did provide important Government communications. Included among these was the wireless connection between the United States and their detached territories in Alaska. This pre-war period was marked by the wide use of heliograph and lamp sig nalling which the Germans made in their i9o5 campaign in South west Africa; and—of far greater import—by the intensive field telephone system in the siege operations of the Russo-Japanese War in 1904-05.
Trench Warfare and Fire Power.—The Powers entered upon the World War in 1914 equipped in varying degrees with line, visual and wireless telegraphy. In organization, military
status and efficiency the signalling services of the armies varied greatly. At one end of the scale was Great Britain, whose signal units were worthy of that "perfect miniature" of which they formed part—the original Expeditionary Force. It seems that the small British army felt instinctively a greater need for efficient intercommunication in war to develop its full striking power, as compared with the vast forces of the Continent, which trained yearly by armies and army corps together and had long ex perience in the administration and manoeuvre of masses. At the other end of the scale stood Russia, putting her trust in numbers and neglecting the means to co-ordinate their movements. It was a neglect for which she paid dearly, and the annihilation of the Russian columns in East Prussia at the hands of Marshal von Hindenburg was due largely to the total lack of communication between them. At the same time the German drive through Bel gium and Northern France, with which the war opened and which so nearly succeeded, owed its miscarriage in part to the failure of the wireless communication which was to have connected their general headquarters with the armies of the right wing. For a few short weeks the tide of battle in the west ebbed and flowed before it settled down to the long-drawn, bloody and apparently fruitless hammer and tongs of trench warfare. The outstanding feature of the latter phase was the overwhelming effect of fire. This, it is true, bad been foreshadowed by the Russo-Japanese War and by progressive developments in magazine rifles, machine guns and both field and heavy artillery, but its terrific power was none the less a surprise to both sides.
Buried Cables and Emergency Methods.—Under the grow ing intensity of bombardment it soon became impossible to pro tect cables laid on the surface, and both sides were forced to put their lines underground ; these were at first only a foot or two be low the surface, but the steadily increasing weight of metal drove them deeper and deeper, until by 1918 six feet was the common depth and new systems were being installed eight feet under ground. Thus on each side as the war went on there grew an im mense gridwork of deep-buried cables, with main arteries every few thousand yards along the front running from the rear up to the forward trenches, joined across by lateral routes. Each buried route might contain i o, 20, 50 or more conductors and the sys tems included hundreds of underground test points and distribut ing centres. In the back areas, comparatively immune from shelling, the buried cables gave place to overhead systems stretch ing back over the lines of communication and conforming to the normal practice of civil telegraph engineering. So we have the phenomenon of rival armies, each seeking desperately to break through its opponent's line and fight in the open, growing more and more dependent upon a telephone system which must inevi tably be left behind if that object should be gained.