XIII ADVANCES IN SIGNALLING CONTRIBUTED TH A. E. KENNELLY HE fighting on land, in the world war, regarded from the American point of view, was waged on a battle line roughly 750 kilometers long, reaching from the coast of Belgium to the Swiss Alps. The center of this line is approximately 6500 kilometers, or nearly 4000 miles, from the War Department Building in Washington, D. C., the army administrative base. It is also approximately 7250 kilometers in a bee line, or 4500 miles, from Chicago, which may be looked upon as the center of gravity of America's supplies for her army. Consequently, America's overseas army of two million men had to join with Allied armies at a distance of more than one-third of the sea-level separation from pole to pole. It was, therefore, of the utmost importance that communication between Washington and the American Expeditionary Force should be kept at the highest point of effectiveness. It is recorded that in January, 1815, the news of the Battle of New Orleans did not reach the capitol at Washington until two weeks after the battle had been fought. That was before the days of the electric telegraph and telephone. If such restricted conditions of communication existed to-day, it is safe to say that no such expedition as America sent to Europe could possibly have been conducted and maintained. In fact, the news of important events at the French front were, in this war, frequently delivered in Washington before the hours at which those events occurred; that is, within the five hours' difference of time between Greenwich and Washington. In that sense, therefore, America knew of the important events of the war before the times at which they happened. Again, in the European campaign of 1815, which precipitated the final downfall of Napoleon Bonaparte, the final battle took place on the field of Waterloo. From the top of a tower 60 meters high on that field, the visitor is shown by his guide the whole scene of tactical operations. On yonder elevation, the French Emperor sat on his famous white horse, directing, by couriers, the movements of his army. Over on this roadway, Wellington rode up and down surveying the battle, and sending verbal orders to his commanders. The battle opened early in the afternoon, and the fate of the Napoleonic empire was virtually sealed before darkness set in. Such was the nature of the last preceding great struggle in Europe, when electrical communication did not exist, and when the first, but unsuccessful experimental electric telegraph was being tried, with frictional electricity, under discouraging conditions, in the back garden of Sir Francis Ronald's house at Hammersmith, in England. At the battle on the European western front in which the A. E. F. participated in 1918, the American headquarters was necessarily remote from the front line more than 200 kilometers from some parts of it. The final battle lasted about four months. Communication had to be constantly maintained by the American headquarters, not only with each division commander at the front, but also with the various reserves, depots and bases, as well as with the Allied headquarters and with the generalissimo in command of all the Allies. Moreover, communication had to be maintained by each division headquarters, not only with its most distant outposts, through brigade and regimental headquarters; but also with its observation balloons, its observation posts, airplanes and tanks. The army was, therefore, extended over a vast network chain of electric communications which ended, administratively speaking, in Washington. Those links of the chains which cross the Atlantic Ocean were supervised by the U. S. Navy. The rest of the network was under the control of the U. S. Army Signal Corps. The duty of maintaining a complete system of electrical communication between Washington and the American Army overseas thus devolved, in large measure, on the Signal Corps. Under the pressure and stimulus of this duty, the very considerable advances in signalling which were made during the war, were largely developed in and by the Signal Corps, so that the story of that advance, from the American viewpoint, is mainly an account of signal-corps achievement. Communication across the Atlantic was maintained mainly by cables underneath the ocean, and partly by radio, or socalled "wireless," over the ocean's surface. The transatlantic cables in service were heavily loaded. A few of them were out of service by breaks, partly due to accident and partly due to war. It was very difficult to make cable repairs in the Atlantic during the war, on account of the dearth of men and repairing ships, and also on account of the vigilance of hostile submarines. Those cables which remained intact were worked at the maximum available speed, duplex ; i.e., in both directions simultaneously, without pause or interval of rest, day and night continuously throughout the year. In describing sustained and unremitting business, the beaver is a common metaphor; but the beaver is a very lame vehicle of expression for unceasing activity; because he sleeps through a fair share of each twentyfour hours. As busy as an Atlantic submarine cable during the war, would be a much more apt comparison for the antithesis to the life of the lily of the field, which toils not, neither spins. In order to supplement the work of the cables, great improvements were made in transatlantic radio signalling, under the auspices of the navy; both as to speed and precision, especially between the naval radio station at New Brunswick, N. J., and a similar station in France. The results attained indicate that even without any new discoveries, or epoch-making inventions, the prospects of long-distance radio communication are im mense, and that the possible capacity for the transoceanic radio traffic of the world is nearly two hundred times as great as that in service during the war; but that is a matter for keeping the future out of the lap of idleness. Before the war, the transatlantic cables from America landed mostly in the British Islands, a few going to France and Ger United States Army system of wires many. One German cable was cut by the British, at sea, in the very early days of the war, and was later diverted to Canada at one end and to England at the other, while another cable of Germany was diverted to France; so that all transatlantic cable communication came exclusively under the operation of our Allies. The Germans, thus isolated electrically under the ocean, kept up a continuous stream of official news and propaganda by radio, into the air from their powerful station at Nauen near Berlin. This continual outpouring of German bulletins continued by radio during the war, and could be read by radio stations over a considerable part of the northern hemisphere, including stations in America. Neutral peoples could receive these bulletins unchecked. In Britain, America, and the countries of their Allies, all known radio stations came under government control during the war, so that except in a few surreptitious instances, these electric waves of propaganda passed harmlessly over the heads of the peoples. Signal Corps Telegraph and Telephone Lines Abroad. On the other side of the Atlantic, the Signal Corps, in 1917, began building and leasing a complete system of telegraph and telephone lines in France and England. The accompanying map, Fig. 1, shows the U. S. Army system of wires in those countries shortly after the Armistice and after communications had been carried forward into the occupied region of Germany. The heavy lines on the chart indicate conductors built and operated by the Signal Corps, the light lines those which were operated by the Corps, but leased from the respective Allied Governments. The system is seen to run from Brest, St. Nazaire, and Bordeaux with their environs, through Tours and Bourges to Paris, and to the American front near Toul and war-scarred Verdun. Connecting Paris with London were two separate leased lines, one crossing the channel near Boulogne, and the other by a special cable near Havre. The Signal Corps built in France about 3500 kilometers of pole line, carrying some 50,000 kilometers of copper wire. Counting 35,000 kilometers of leased wires, 120,000 kilometers more for networks of telephone wire from the various headquarters to the front, and 150,000 km. of locally erected army telephone wires, the Signal Corps wire system comprised a total of approximately 358,500 km. of wire in France and England, or nearly enough, if spliced end to end, to reach to the moon. The traffic which this army telegraph system had to carry |