Page:EB1922 - Volume 31.djvu/351

was arranged for fragmentation and it had a direct-action Ignition system. The maximum range was nearly 400 yards.

ifety Pin

Body ofGrenadt

Special Cartridgi

Sleeve with

Vanes

Wad

Etpamion Chamber

Discharger

Barrel

Attachment

Regulating Pin

FIG.15

The German discharger-cup grenade, introduced m 1918 to replace rodded grenades, was in all but details a copy of the French V.B. It ranged to 150 metres. The ignition arrangement was simpler than in the French archetype.

The Russians also used a discharger-cup grenade in addition to their rodded rifle grenades. The grenade for this fuze had an adjustable time ring. (C. F. A.)

The Grenade of the Future. In Great Britain, a reconsideration of grenade problems in the middle of 1917 led to several modifica- tions in the Mills grenade as such (the new pattern being designated No. 36) and in particular to the design of a discharger-cup for it. The rod was abandoned, and replaced by a steel disc 2 5 m. in diameter attached to the base plug. This fitted accurately into the cylindrical portion of the cup, and the whole of the escaping propellant gas was therefore usefully employed. This cup was used on active service in the last months of the war.

Meantime, research had again been directed to the percussion hand grenade. Various types had been tried but, owing chiefly to the fact that the Mills had become thoroughly familiar and was trusted by the army, none was actually adopted.

The fusion of hand and rifle grenades, however, was not imminent, and amongst the conditions laid down for the " grenade of the future " were that it was to be (i) a percussion grenade, but one that would act in any position of impact or fall without the necessity of any form of air-drag; (2) capable of use either as a hand grenade or as a rifle grenade; (3) safe (a) during the first 10 yd. of flight and (ft) if dropped or accidentally knocked prior to throwing, but sensi- tive beyond 10 yd., even should it fall in soft mud; capable also of being picked up and thrown away when lying on the ground with all safeties removed ; (4) weatherproof and mudproof ; (5) simple to manufacture, to assemble in the field, and to use.

The last two conditions are obvious necessities in a service gren- ade required in vast quantities. The other three, however, involve technical questions of design and are largely interdependent. Thus, requirement (i) might be met by rotating the grenade by grooves in the discharger-cup and ridges on the grenade or vice versa (thus ensuring nose-first impact) were it not for_requirement (2), and in requirement (3) the significance to the designer of the lo-yd. fron- tier between " safe " and " sensitive " is different according as a hand-throw or an explosive propulsion is in prospect. A discussion of these requirements in detail, the technical elements available for meeting them, and the experimental patterns which have been evolved in accordance with this schedule of conditions lies outside the scope of this article. It must suffice to say that the problem thus set is one of great difficulty, but that, with the harvest of expe- rience gained in grenade design during the war period, it is by no means insoluble. One or two questions of a general character should however, be mentioned in conclusion.

The range and weight of the grenade of the future will depend undoubtedly on the final interpretation of the lessons of the war. The tendency to increase range will be checked at some upper limit fixed by the capacity of the infantryman's standard weapon to endure the strain. Beyond that limit a special weapon will be

rench mortar, but in either case its projectile will cease to be a grenade in the ordinary acceptation of the term. On the other hand he lower limit of weight of projectile remains fixed by the necessity of producing adequate effect on explosion. Under existing condi- tions it may be stated, as a rough indication, that the lower limit of weight compatible with effect is hardly, if at all, below I lb., and hat 300-350 yd. represents the upper limit of weight for if-lJ- b. bombs fired from a discharger-cup fitted to the ordinary rifle.

Another question of importance is the means used for varying the range. As a hand-thrown weapon of course the grenade is wrought on to its target by the skilled eye and hand of the thrower, aut as a rifle grenade it requires mechanical adjustment. During

he war, special rifle-grenade stands were designed, into which the

rifle was clamped, but such devices may be considered as proper to trench warfare only, and the problem of the present day is to find a means of varying the trajectory of the grenade which is adaptable to the individual rifle. Two solutions have offered them- selves. One is varying the pressure of the propellant gas by vary- ing the position of the grenade in the cup, as in the French D.R. grenade and mandrin, the discharger-cup used in the last months of the war for the Mills grenade, and other types. Opinion is divided on the merits of this method, which, though attractive in other respects, is open to criticism because it does not legislate for wind a specially important factor in shooting with a large object of low velocity such as the grenade, and also because such an adjust- ment may easily be forgotten or mis-set in battle conditions. The alternative is to provide a simple form of clinometer or elevation indicator on the rifle. (C. E. W. B.)

GRETNA (see 12.583*). A new association was given to the village of Gretna in 1915, when the Ministry of Munitions pur- chased a site for the erection of a large propellants factory and for houses to accommodate munition workers. The strip of land taken for the purpose was roughly 9 m. long by i m. broad, and extended from the village of Dornock on the west to Long- town on the east. The factory was erected to make the ex- plosive known as cordite R.D.B., which had been recently invented by the Research Department and was made without the use of acetone, of which supplies were short.

An area of 7,715 ac. of lightly farmed arable and pasture land was taken under the Defence of the Realm Act in July 1915, and was subsequently increased by 1,399 additional ac. in order that the factory might convert into cordite both its own nitro-cellulose and also that produced by a factory at Queensferry. One factory was divided into separate areas for the successive processes of manufacture, and materials were carried by an elaborate system of specially constructed railway lines. The full output of 800 tons of cordite per week was attained in the beginning of 1917, and the total amount of cordite produced was 56,876 tons. The maximum number of construction and operating workers employed together was 24,700, but the number of operating workers had been reduced by the date of the Armistice from 20,000 to 1 1,000. The proportion of female to male labour was about seven to three. For the accommodation of this large staff, factory townships were erected; the two largest of these were Gretna, with an area of 431 ac., and Eastriggs, near Dornock, with an area of 173 ac. The total number of dwellings erected included 670 timber huts, 54 timber hostels, 310 brick or stone houses, and 134 brick hostels, accommodation being provided for 13,485 persons. -The villages contained shops, halls, cinemas, recreation grounds, schools and churches, and excellent supplies of water (from the river Esk) and of electric power were provided, both for industrial and for domestic use. Surplus land was cultivated and provided large supplies of oats, potatoes, garden produce and hay. The townships were administered by a town manager who controlled housing and public services, and the factory was made a sp2cial police area. The health of the factory was very satisfactory; the total number of deaths was 145. When the factory was gradually closed down after the Armistice many of the workers were allowed to remain in the houses, though they had to find employment else- where or in the repair of railway wagons, which was introduced to relieve unemployment in the area. At the end of 1920 there were still some 600 operatives employed in the maintenance of the build- ings or in some other work connected with the factory ; but, after considerable hesitation, it was decided not to retain it for national purposes and it was offered for sale in the autumn of 1921.

GREY, ALBERT HENRY GEORGE GREY, 4 EARL (1851- 1917), British statesman, was the son of Gen. Charles Grey, Queen Victoria's private secretary, and grandson of the 2nd Earl, the Whig Prime Minister who passed the Reform bill of 1832. Born Nov. 20 1851, he was educated at Harrow and at Trinity College, Cambridge, where he graduated with a first-class in the law and history tripos, 1873. As his uncle the 3rd Earl had no children, Albert Grey was the heir-presumptive to the earldom, and he endeavoured to win a seat in Parliament as a Liberal, when a by-election occurred in S. Northumberland in

required, and this will either compete with or fuze with the light

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