instead of one. 1 Not only did the French not employ lateral lines, but it was only under suasion that they would make use of them when provided.
The front-to-rear forward routes were mainly of buried cable, though shallow splinter-proof and traffic-proof trenches and narrow open trenches were also employed. " Comic " airline, that is air- jine built with improvised poles and other stores, which was an invention of the British army, was also adopted by the French, but the latter placed more reliance on fairly heavy routes of poled cable, especially of 7 or 8 cables slung together on pickets 3 to 4 ft. high, a method seldom employed in British divisions except when working in French areas, but which proved very satisfactory when used by a British corps in the advance from the Marne in July 1918.
A further divergence of practice was the concentration upon continuous wave wireless to the exclusion of spark wireless for for- ward command purposes which was the outstanding characteristic of the forward French wireless service. In 1918, continuous wave wireless was used for command purposes in armies, corps, and divi- sions and the wireless system achieved a considerable measure of success in the final advances of the autumn. This was the logical outcome of the fact that, on the Allied side, the French were through- put the pioneers of the development of the 3-electrode valve and its application to practical war problems. In no army were the research departments of the signal service keener or better directed. The chief triumph achieved was the designing of such a valve of a much more robust type than any previously produced. This valve, known as the " French " valve, became the standard equipment for the majority of the forward wireless and listening sets both in the French and British armies. (R. E. P.)
(7) The German Signal Service. In the German army before 1914 the signal service formed part of the " Communication Troops " ( Verkehrstrupperi) which had been separated from the engineers for some years. Six Prussian, one Saxon and two Bava- rian telegraph battalions existed, and these units, as well as the regimental signal personnel, were trained principally in the buz- zer telephone. Wireless telegraphy was provided for by separate detachments, in principle destined for G.H.Q., army headquar- ters, cavalry formations, and important fortresses. The only other means in use by the signal service of the field army of 1914 was the visual apparatus (Blinkgerat), but this was not regarded as having any value in battle, for which the intention was to depend on good tactical and technical handling of the telephones. The strength of the signal service in peace was about 8,500, increased on mobilization to 26,000, and at its maximum in the winter of 1917-8 the establishment reached 192,000. This was nearly an eightfold increase in numbers, but as the number of formations provided with signal units had itself increased, it is more instructive to compare the signal personnel of an army of given strength in 1914 and 1917-8. In the former year, a Ger- man army of 12 divisions had about 1,900 signal personnel, and in the latter (nominally) some 9,300. Comparison of these figures with those given above for a British army of 6 divisions in 1914 and in 1918 shows that the German army was at the outset less well-provided than the British, as was indeed to be expected from the long tradition of colonial wars of the latter. At the end of the World War, however, the German signals were, nominally, slightly superior in numbers to the British, though in practice, as the German system assigned to signals certain duties that were not so assigned in the British organization, the strengths or rather establishments were about equal for a given force. 2
In the first German operations in the western theatre in 1914, intercommunication was in principle by the telephones of the signal service from supreme command to brigade headquarters and by the telephones of the regimental signalling sections (at first, eight men per battalion) farther forward. The flag was also in use, but, as in the British service, it soon disappeared when tested by war. Between the supreme command and armies and cavalry formations, wireless telegraphy especially in the later stages of the advance to the Marne, when the army telephone detachments failed to keep up with the march was the principal means of communication and was supplemented by missions of staff officers carried in motor cars. It is admitted by all German critics that this liaison proved far too loose, and its defects are considered to have contributed very largely (some say, principally) to the defeat of the Marne. The for-
1 With British formations amongst themselves the convention was for each to open and to maintain communication with its left- hand neighbour.
- Throughout this comparison, regimental signalling personnel
is ignored.
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ward telephones, on the other hand, in corps signal and in regi- mental charge, met the demands made on them, to the surprise, it appears, of the army generally, which at the outset had little faith in the utility of technical aids on the battlefield and believed the runner or despatch rider to be the only really trustworthy means of intercommunication. The reconnoitring cavalry was particularly well equipped with telephones, and used a light wire, enamelled to give some degree of insulation to the line in wet weather.
Common to all branches of the intercommunication service was the principle of building from front to rear. Army detachments were responsible for making connexion with the supreme command, corps detachments with army headquarters, and so on. The western campaign of Aug. and Sept. 1914 demonstrated almost at once that this principle was unsound, but only after the penalty for imperfect liaison had been paid.
In the eastern campaigns of 1914-5, and to some extent also in the Rumanian campaign of 1916, conditions imposed upon the Ger- mans radical departures from pre-war regulations. Firstly, the sig- nal units of Hindenburg's armies of 1914 were largely improvised, like many other services and even combatant troops in the East. Secondly, the sparseness of communications and the difficulty of movement compelled the German command from the first to manipu- late its signal resources in accordance with the operations in hand or in prospect instead of attempting a schematic layout of lines to all formations alike. Thirdly, the initial mobile warfare conditions continued in the East for more than a year of constant campaigning, and at a later stage, the Rumanian campaign came to prevent the les- sons of open warfare from being forgotten. Lastly, the operations began on friendly territory and the policy of the signal service was to build forward from the home telegraph system. These condi- tions led to (a) enhanced importance of wireless telegraphy, (6) economy of cable, and the use of airline close up to the front, (c) the return to telegraphy for work in rear of corps and even division head- quarters, and consequently the development of quick-writing tele- graph instruments, 3 and (d) the principle of concentrating both wire and wireless communication on a central route connecting a head- quarters with a forward report centre (Meldekopf, report-head) in the region of the advanced guard, a principle which, for quite differ- ent reasons, came into honour later on the western front. The importance of wireless was again emphasized in the Balkan cam- paign of 1915 and the Rumanian campaign of the following year, in which also the visual apparatus rendered good service.
In the position-warfare campaigns of the West, evolution speaking very generally followed the same course on the German side as on the British, similar difficulties and problems naturally suggesting similar remedies. It has already been noted that the numerical growth of the signal service in relation to other arms was approximately the same in the two armies. As regards organization, an important difference was that on the German side the basis of classification was, to the end, the instrument used and not the formation served. Although the signal service branches were com- bined in one corps of Nachrichtentruppen in May 1917, this was sub- divided at all echelons into telephone units, wireless units, and visual units. The first-named were responsible for telephones and tele- graphs (the latter being largely employed from division head- quarters rearward), the wireless detachments for wireless of all kinds and power buzzers, and the visual detachments for the Blinkgerat. Moreover, the listening sets, the pigeons and the dogs, were all organized administratively as separate sections of the corps. But in each headquarters, from supreme command to divisions inclusive, the Nachnchtenkommandeur was a member of the formation staff and was responsible not only for the command of his own units but also for communication arrangements and procedure generally within the formation, including regimental signallers of infantry, cavalry and artillery, in his capacity as a staff officer. The control and manning of aircraft wireless stations was also in the hands of the signal service, as well as wireless police and wireless intelligence, and (again in his capacity as a staff officer) the divisional signal commander performed many functions that in a British division were assigned to the intelligence officer.
The possibility of applying the recently discovered "audion," or 3-electrode valve, to the purpose of overhearing the opponent's tele- phone conversations was first realized by the Germans, and the success of this innovation may be said to have revolutionized signal practice on both sides during the war. It made closed metallic circuits in the forward lines and strict telephone discipline essen- tial, and, further, from the listening set there came the " earth tele- graph " (power buzzer) which played so important a part in the signalling of all armies in the last two years of the war. But, quite as important as these applications of the 3-electrode valve was its effect on wireless telegraphy through the air. It made possible the change from the spark to the continuous wave system, by providing (a) an intensifier for small, weak receivers such as those of trench and aeroplane sets, and (b) the means of very sharp tuning which allowed of many sets being employed together in a restricted area without mutual interference. Satisfactory trench wireless apparatus on the continuous wave system was designed in 1915 and used in
3 The Siemens Schnellfernschreiber is said to be capable of dealing with 1,000 letters a minute.
