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orders went to special factories, in others to cooperative groups, the whole organization being. bound together by a local office of the Ministry under a special directorate (in charge of Mr. James Stevenson) at headquarters. The supply of heavier shell was met by orders with armament and other selected firms, but when the programme was increased in Aug. 1915, it was decided that "na- tional projectile factories " should be built for the Ministry and managed by the various experienced firms on a commission basis. These factories, laid out for a special purpose, ultimately proved highly efficient in mass production and enabled an enormous sav- ing to be made in cost. Additional orders for both light and heavy shell were also placed in America and Canada.

Experience proved, however, that light shell could be turned out much more readily than fuzes and other components, and they began to come forward rapidly and before the filling factories were ready to deal with them. The American share of the programme had also been ordered for early delivery. Hence, by the summer of 1916, an enormous stock of light shell had accumulated, partly as a deliberate policy and partly from fortuitous causes. At various dates, there- fore, in 1916 light-shell orders in America were allowed to terminate and output at home cut down, and the machinery partly turned on to heavy shell.

The new artillery programme of July 1916, however, based upon experience on the Somme, not only absorbed the surplus Ministry orders for heavy artillery, but also raised the daily am- munition ration for heavy guns. The Minister was still uncertain what output would be attained in the national projectile factories, which were only then coming into production, and therefore al- most his last act at the Ministry was to place large orders in America and Canada, in the two natures in which the biggest increase was asked for, viz. 8-in. and g-2-in. shell.

Shells could be made in any engineering shop; but explosives could only be handled in factories built for the purpose. Hence, as soon as the ammunition programme was settled the ammunition depart- ment set to work to plan and to build a dozen large filling factories, which were rapidly completed and began to handle shell in Feb. and March of 1916. The task of these factories was, however, not merely the technical one of filling shell, making cartridges or filling fuzes, but also that of assembling all the necessary components in proper proportion and of handing to the army in complete con- dition as rapidly as the Ordnance Department could accept de- livery. At Christmas 1915 -the organization of these filling fac- tories was divided from ammunition manufacture and handed to a new department. During the spring their work was delayed not only by inexperience, but also by the inability of the technicians to find a satisfactory fuze for detonating amatol filled H.E. shell which would avoid the Scylla of over-sensitiveness, with the resulting casual- ties to the troops through prematures or gunbursts, and the Cha- rybdis of excessive safety, resulting in " blinds " and ineffectiveness against the enemy. Work at the highest possible pressure at Wool- wich at last solved the problem, and solved it so satisfactorily that, a year later, British artillery was probably more immune from prematures, etc., than any other. But the constant change of processes during these critical months held back the factories from getting on with bulk production, and it was not until the middle of May that the Ministry began to hand over large supplies to the army. The date of the Somme offensive was largely deter- mined by these considerations.

Explosives and Propellants. Special steps to develop the pro- duction of explosives were taken in 1914 the problem of increasing the output of tri-nitro-toluol (T.N.T.) and other explosives being remitted to a committee under the presidency of Lord Moulton. Hence, when the Ministry was formed, plans were not only in hand but had already achieved considerable success. Pressure had been put upon gas undertakings throughout the United Kingdom to extract the utmost amount of the by-products of coal distillation at the expense of the illuminating-power of their gas, in order to increase the supply of toluol and of benzol, which Great Britain had begun to supply to France. When the Ministry was formed Lord Moulton's department was transferred, and charged in addition with the supply of propellants. At that time this consisted almost entirely of cordite, of which the supply was fairly ample owing to the large capacity which had been developed for naval purposes.

When, however, the new ammunition programme was decided upon, it was evident that the supply both of H.E. and of propellants would also have to be enormously increased. So far as explosives were concerned it was evident that the world's available supplies were insufficient to enable the programme to be carried through by means of either pure T.N.T. or picric acid. It was known that in theory a mixture of T.N.T. and ammonium nitrate could be made to produce as violent a detonation as pure T.N.T., and that the French army was in fact using a mixture of picric acid and am- monium nitrate. In order not to compete for the supplies of picric acid, it was decided to rely upon a mixture of T.N.T. and ammo- nium nitrate (amatol), and the design department was set to find a means of satisfactory detonation.

The result of their efforts was that during the war, out of about 625,000 tons of explosive supplied, only 210,000 tons (of which 35,000 tons were imported) was T.N.T., less than 80,000 tons picric acid, and the rest ammonium nitrate.

In the case of propellants the stocks and manufacturing capacity for cordite in autumn 1915 were fairly large, and as early steps were taken to increase output its supply never delayed the ammunition programme throughout the war. Its production was, however, lim- ited by the supplies of acetone, and even when an ether-alcohol solvent was used as an alternative to acetone, it was not possible to meet the enlarged programme by cordite alone. The army had accepted as propellant for certain guns a nitro-cellulose powder, which was the standard charge on the Continent before the Min- istry came into existence, and since it was not manufactured in England orders had already been placed in America. One of the earliest acts of the Ministry was to place, with Messrs. Dupont of America, enormous additional orders sufficient to justify the manu- facturers in making large additions to their plant.

From that date onwards the question between cordite and nitro- cellulose continually exercised the minds of the Ministry. The argument for importing finished propellant was the great saving in tonnage involved, since it is necessary to assemble several tons of material for each ton of propellant and nearly_ all ofr the material had to be imported mostly from very great distances. This advan- tage had, however, to be balanced against the consideration that, so long as Great Britain remained dependent on a neutral country for a substantial proportion of its propellants, the supplies were out of British control so far as the manufacture was concerned, were liable to serious losses from submarine activity, and in danger of interruption should the United States Government for any reason desire to prohibit the export of munitions. Towards the end of 1916 the last of these considerations assumed considerable impor- tance; and as at that time the use of nitro-cellulose had been adopted for a considerable number of types of artillery, it was decided to commence the manufacture of nitro-cellulose powder in Great Britain. A large factory was projected, but was abandoned when America came into the war.

The novelty of the supply both of explosives and propellants led to the building of large national factories to supplement the limited capacity of the factories in private hands. Indeed, the largest indus- trial venture of the war was the propellant factory at Gretna, the scale of which is illustrated by the fact that its acid-producing capacity exceeded that of the whole country before the war. As it was considered expedient to build not only out of range of enemy aircraft but also away from industrial centres, it involved building a town to house the workpeople. The factory, which cost 8,000,000 to build, made nearly one-fourth of the cordite required by the army during the war, at a considerable saving of cost.

The relative importance of home sources and of imports of ex- plosives and propellants is shown in Table I, which gives the percen- tages of the total output during the war :

TABLE I.

Trade

National Factories

Imports

Picric Acid. . . . T.N.T. ... .. Ammonium Nitrate All Explosives Cordite ... .. Nitro-cellulose All Propellants

92% 21

65

53

47

26

6*% 63 3 39 38

2 22

ii%

16

5 8

15 98

52

The explosive output involved a greatly increased supply of nitrate from abroad. At first this was readily forthcoming, but at an early date Allied competition led to difficulties in Chile, and later, when lack of tonnage made it difficult to spare ships for so long a' voyage, an inter-Allied organization was set up to buy for the Allies in common and to ration supplies. In the last year of the war France met her needs to a substantial degree by the fixation of atmospheric nitrogen; but though a plant for this purpose was begun in Great Britain it never reached the production stage.

Trench Warfare. The stabilizing of the western front led to the employment of a great variety of engines of war subordinate to the artillery, such as mortars, hand grenades, etc., some of which were designed and even produced at the front. These weapons gave great scope for inventive faculties, while the implements themselves did not require the same degree of accuracy as artillery or aeroplanes. Hence they provided an outlet for engineering capacity which was not suitable for more exact munitions, while it enabled civilian enter- prise to make substantial contributions on the side of design. The trench warfare department of the Ministry was in fact organized on the principle of setting " design " and " production " side by side. It produced a large number of products which it offered to the army, of which three are of outstanding importance. (l) The first was the Stokes mortar, which was manufactured and sent to the front in spite of a very lukewarm reception by the military authorities. In this case the Ministry proceeded in advance of the sanction of the War Office, but the weapon won its way and became part of the standing equipment in the latter years of the war. (2) The depart- ment in the autumn of 1915 experimented with shell filled with lachrymatory gases, and, in the spring of 1916, with poison gases of various kinds. The most powerful of these was at first withheld from use by the army, as the Government was unwilling to go farther in