in 1918. Interesting and significant figures are given by the same author as to numbers and losses in personnel, and expenditure of materiel. In actual flying personnel at the front, the hjghest total present at one time (in 1918) was about 5,500, with a like number under training at home. The total deaths of flying personnel or candidates in the war numbered 6,840, of whom about two-thirds died at the front. The number of wounded and injured (7,350) is little more than that of the dead. Approximately 2,128 planes were lost under known circumstances (about 1,900 of these on the western front). In addition about 1,000 missing were presumed as lost. In all, 47,637 machines and 40,449 motors were taken on charge from contract. The monthly expenditure of fuel at the end of the war was 7,000,000 kgm., and the total for the whole war about 232,000,000 kgm. Rather over a million bombs were dropped, of which 860,000 were of the 12-kgm. type and 710 of the monster i,ooo-kgm. type.
The organization of German naval aviation before the war was considerably in arrears as compared with that of army flying. The predominance of the airship was the main cause of this, but other causes contributed, especially, it is said, the lack of interest in sea- plane design on the part of manufacturers, whose establishments (except that of Friedrichshafen) were far from water. The first seaplane competition, organized by a few enthusiasts, was to have been held on Aug. I 1914. Only some 20 naval officers had been trained as pilots in the single existing seaplane station.
These conditions continued to hamper progress for some time after the outbreak of war, as the army impounded all the motor manufac- turing resources for its own needs. Nevertheless, seaplanes were established on the Flanders coast by Dec. 1914, and thereafter the organization of the seaplane service expanded till there were finally 32 stations in the different theatres of war and on the German coast. For naval work, the organic unit was the station ; the equipment, of course, varying according to the work expected of each station.
At the same time, a number of aeroplane flights organized as such, were created by the navy for land service, of which nine or ten served in the eastern and south-eastern theatres. The other fifteen, in Flanders, belonged to the Marine Corps, a mixed organization responsible for the land defence of the Yser front, the coast defence of the Belgian coast and the submarine operations based on that coast. The commander of Flying Troops of that corps had under him a correspondingly mixed air force.
Naval aviation generally was under the control of a naval avia- tion chief, who was independent of the army air authorities.
Airship Organization. In spite of the popular enthusiasm evoked by the work of Count Zeppelin and other airship constructors before the war, the naval and military authorities were not, before the war, very ready to commit themselves to a strong and permanent air organization. The army airship organization dated only from 1906-7 and the naval from 1910-1. The army acquired Zi in 1906 and Z2 in 1909, and after the wreck of the latter, a pause occurred in which commitments were avoided pending further competitive experiments between the Zeppelin, Parseval and Gross types. In 1912, however, the decision went in favour of the Zeppelin and the Schiitte- Lanz, and airship battalions were formed to fly and to maintain airships.
At the outbreak of war the army possessed seven ships (six Zeppelin and one S-L) of the rigid type, and two others, and took over three more from private ownership. Organization, nominally by battalions, was in reality dependent on the number and station of ships. This rapidjy increased. But from the first there was a strong current of opinion adverse to the airship in land warfare, and the authorities concerned with personnel looked with disfavour on the huge landing parties which the ships required at each station. In spite, therefore, of the occasional achievements of individual ships, 1 it was decided early in 1917 to discontinue the army airship service. The still useful snips were handed over with part of the air personnel to the navy, and the remainder of the personnel was allocated to the army kite balloon service.
Excluding Parseval and small airships the manufacture of which was discontinued at the outbreak of war 37 Zeppelin and 10 S-L ships were commissioned by the army from first to last, of which 17 were lost in action, 9 lost from other causes, 17 scrapped, and 4 handed over to the navy on discontinuance.
The navy, on the other hand, beginning later than the army, went on developing the airship service to the end of the war. In Aug. 1914 it possessed only one ship, obtained from the Zeppelin company to replace Government ships lost in 1913.
Inclusive of the effective ships taken over from the army in 1917 74 ships were commissioned for naval service, of which 23 were lost in action, 30 from other causes (4 by lightning), and 1 1 were scrapped.
Kite Balloons. The development of dirigible airships and of aeroplanes, in Germany as elsewhere, thrust the captive balloon
1 In many respects the most remarkable achievement of airships in the war was the voyage of L59 in the autumn of 1917. This was a naval ship, but the service in question was overland. Starting from Yamboli in Bulgaria the attempt was made to reach von Lettow- Vorbeck in E. Africa with medical and other small and valuable stores. This ship was recalled by wireless after passing Khartum, but returned safely, after a 7,ooo-km. voyage lasting 96 hours. The record for endurance, however, was held by LZi2O (loij hours).
into the background, and although 8 field and 15 fortress balloona were mobilized in 1914, the question of their abolition was actually being considered when the unexpected coming of trench warfare opened up a new field for them. Early in 1915 the introduction of power winches (at first improvised in the field) and of the parachute added greatly to their efficiency, and by the end of that year more than 40 sections, each of 2 balloons, were in the field. But the war experience of 1916, and notably the sight of Allied sausage balloons, hanging in the air " as thick as grapes," compelled the army au- thorities to develop their kite balloon service at a faster rate. The organization, hitherto in single unconnected sections, was expanded to provide over 50 staffs, each of which controlled 2 to 3 sections of balloons. In the end, 184 such sections existed in the field, as well as a certain number lent to Turkey or employed in instructional duties. In the latter part of the war the admittedly inferior balloon of German design was replaced by one of the Caquot type, a captured specimen being copied almost exactly.
In all, 1,870 kite balloons of all types were delivered from contract and about 350 power winches. In course of the war about 600 bal- loons were lost in action (75 % to 80% by aeroplane attack), 100 by weather and other causes, and 500 condemned as unserviceable.
The Meteorological Service in the German army formed part of the air forces, although its observations and reports served the ar- tillery, chemical warfare and other branches as well. At the begin- ning of the war an embryonic organization already existed, with a central section at Berlin, 14 sections at airship stations and aero- dromes and 2 sections organized on a mobile basis. These last at once expanded to 8 (one per army) and by the close of the war these 23 units had grown to a total of 316.
The general lines of the organization were as follows: (l) The Berlin H.Q. ; (2) Western Front H.Q. at Brussels; (3) Eastern Front H.Q. at Warsaw; (4) South-eastern Front H.Q. at Temesvar (later Sofia), and (5) Turkish H.Q. at Constantinople. Under each of these (except the last) there were in strength varying according to condi- tions, Haup/welter Warten, which were concerned with focussing information from Berlin, from the naval weather service, and from the front, and also with local meteorological services for troops behind the line in occupied areas (e.g. flying schools); and Armee Wetter Warten which had the chief tactical and technical respon- sibility at the front, and controlled a network of minor units, some attached to particular services but most distributed on an area basis.
Air Defence. In Germany and at the front the commanding general of air forces was responsible for air defence. A few mobile guns only were available for anti-aircraft work in 1914, but the 75-mm. guns captured in the advance to the Marne and -especially the high velocity Russian field guns taken on the eastern front, provided a considerable A. A. armament, pending the design and supply of special ordnance. By the end of the war the original 20 guns had grown to a total of over 2,000. The evolution of technical adjuncts of air defence, searchlights and direction-finding detectors (see AIR DEFENCE), proceeded as on the Allied side.
As regards organization, after various alternative methods had been tried, the Germans separated off all " Flak " (Flugabwehr Ka- none) troops from the rest of the artillery and centralized the control in each army area in the hands of a special officer, to whom all sub- ordinate Flak commanders were alone responsible though they were authorized to advise corps commanders on the technical aspects of air defence in the corps area. In 1916 the Flak service passed with the rest under the control of the new commanding general of air forces; thenceforward all the means of air defence were coordinated under the same authority in each area, both in the field where " Commanders of air forces " (see p. 87) exercised local control, and in Germany, where a deputy of the commanding general was re- sponsible for defence of munition areas. This organization ensured an intimate connexion between guns, aeroplanes, observation posts and lights, based on a common doctrine taught in the Flak depot at Freiburg and in Flak schools at the front.
VII. UNITED STATES. In the United States, as elsewhere, the organization of air forces before the World War was in its infancy, and although between 1914 and the entry of the United States into the war a certain amount of air research and training had been carried on, and some practical war experience gained in Mexico, yet their position as neutrals prevented the American authorities from obtaining technical data concerning the progress in aviation that was evidently being made by the belligerents.
In April 1917, therefore, when the Allies invited America to train and equip a force of 5,000 aviators for service in Europe, there was little likelihood of the demand being met. At that date the American forces possessed 55 machines of which a scientific commission had just declared 51 to be obsolete, and about 75 trained officer pilots.
The first necessities, therefore, were instructors and training machines. Of the latter, or rather of a type of the latter considered good enough for primary instruction, delivery in quantity began before the winter of 1917, and by the Armistice there were about 9,500 planes and 17,500 engines suitable for training.
The need of instructors was met partly by borrowing _British and French officers, and partly by retaining the best pupils in the early classes to become instructors to those formed later. In the sequel, 8,600 pilots were graduated from the elementary courses and 4,000 from the advanced courses before operations ceased, and some
