Encyclopaedia Britannica, 11th Edition, "Armour Plates" to "Arundel, Earls of"

that, provided unity of direction is kept, an overwhelming artillery surprise (see _F.A. Training_, 1906, p. 225) is carried out more easily than from a visible position. The extent of _front_ of a battery in action is governed by the rule that no two gun detachments should be exposed to being hit by the bullets of one shell, and also by the necessity of having as many guns as possible at work. These two conditions are met by the adoption of a 20-yards interval between the muzzles of the guns. At the present time the gun and its wagon are placed as close together as possible, to obtain the full advantage of the armoured equipment. The _shield_, behind which the detachments remain at all times covered from rifle (except at very short range) and shrapnel bullets,[3] enables the artillery commander to handle his batteries far more boldly than formerly was the case. General Langlois says "the shield-protected carriage is the corollary to the quick-firing gun." Armour on the wagon, enabling ammunition supply as well as the service of the gun, to be carried on under cover, soon followed the