PRESIDENTIAL ADDRESS. 257 



manufactured during the war was 20,000, and over 200,000 machine guns had 

 been delivered by November 1918. 



The Ministry of Munitions took charge also of the production of aircraft, 

 which were liltimately turned out at the rate of 4,000 per month ; later the 

 provision of motor transport was in addition placed under its control. Finally, 

 our production of ' poison gas,' for which this Ministry was responsible, rose 

 during the last few months of the war to several thousand tons a month, sufficient 

 to make the Germans rue the day on vi^hich they had introduced this weapon 

 into warfare. 



Among the inv^sntions which have had an influence on military operations I 

 will mention only three as typical of three distinct classes : 



1 anks were first used in 1916. and the results produced were greatly enhanced 

 by the surprise created, and consequent moral effect, but the idea of an armoured 

 chariot is as old as organised warfare. The problem of constructing a vehicle 

 which could travel across the trackless and shell-pitted district which extended 

 between the two armies remained to be solved. In the light of the experience 

 gainedi with various types of tractors ft was, however, clearly not insoluble, and 

 credit is due to the man who had the courage to hazard a novel and important 

 experiment. The resulting tank was the product of careful design and experi- 

 ment, and the oiitcome of the co-operation of several engineers with special 

 knowledge. Sound-ranging introduced the complex methods and delicate instru- 

 ments of physical research into the trenches, and, against all precedents, proved 

 them to be reliable and practical under the most adverse conditions. The 

 Stokes g(un, on the other hand, superseded all other trench mortars by simplicity 

 of design of manufacture and convenience in handling ; 20,000 of these guns were 

 used during the war. 



Transport. — On "August 4, 1914, the Government assumed control of the 

 railway systems in this country, but the working and management was left in the 

 hands of the railway officials, and to them is due the smooth working of the lines 

 during a long period of exceptional difficulty. British engineers, civil or military, 

 liave been responsible for the transport through France, and during the last two 

 years of the war large numbers of engines were sent across the Channel and 

 miles of track v/as taken up in England and relaid in France. Road transport 

 was organised on an unprecedented scale, and 100,000 new vehicles were de- 

 livered. A network of narrow-gauge railways was can-led right up to the 

 trenches, and numerous new roads, railway lines, and bridges construct-ed. Rail- 

 way constniction formed an important factor in connection with the advances 

 in Mesopotamia and Palestine; in the latter case the entire water supply had 

 for a long period to be drawn from the Egyptian base through a specially laid 

 pipe-line. 



In France and elsewhere the armies were primarily dependent upon sea 

 transport for their food and equipment. This service, organised by the Navy, 

 culminated in the unique effort which brought American troops at the rate of 

 300,000 per month, and thus overbore the balance which for four years had 

 been oscillating between defeat and victory. 



Among the notMble new departures the cross Channel train ferry and the 

 portable steel bridges, principally of the Inglis type, should be specially 

 mentioned. 



Navy. — At the outbreak of war the Nav>- was ill-prepared with regard to anti- 

 submarine defence and mining. The influence of the submarine on naval warfare 

 had been under-e.stimated, and mines were regarded as a somewhat discreditable 

 means of destruction; but dining 1915 the depth-charge and the Paravane were 

 developed bv the naval experimental department at Portsmouth, and later 

 thousands of these were brought into use. In principle the depth charge consists 

 of a canister containing a large charge of explosive and a pistol actuated by an 

 hydrostatic valve. The merit of the invention resides in the simplicity, safety, 

 and reliability of the mechanism. In designing the Paravane the iDodv was 

 borrowed from a torpedo, and wings, rudder, and elevator from an aeroplane. 

 The secret of the device lies in the stabilising mechanism, which enables it to 

 keep its position when the ship is running at high speeds. The Paravane enabled 

 most ships to pass unscathed through a mine-field, and in a slightly modified 

 form it served to seek out and destroy submarines under the water. 



Sound location proved to be one of the most valuable inventions developed 



