The introduction of machinery on a large scale put to flight the old traditions of the Arsenal, and the manufacturing spirit had to be substituted for the military organization under which the establishment had been conducted before. Such was the energy and rapidity with which the old Arsenal reformed itself, that we question if any private factory in the kingdom is conducted upon a better system than is already at work there. Within these three years factories have sprung up on every side, and the whir of wheels, and the measured stroke of the steam-engine, can now be heard over the whole of its immense area. The three manufacturing departments into which the Woolwich Arsenal is divided are as follows:--The Royal Gun Factory, the Royal Carriage Department, and the Royal Laboratory Department. Through these factories we will conduct our readers, and endeavour to give them an idea how human ingenuity has perfected the means to destroy human life. The gun factories, by right of age, take precedence, although in point of interest they present the least attractive features to the spectator. The fact which most strikes him as he threads his way amid the Cyclopean machinery is the slow, inevitable manner in which the different processes are carried on. Here you see a large lathe turning the outside of an eighteen-pounder, revolving as noiselessly and as readily as though it were only turning a brass candlestick--a fixed tool cutting off its thin shavings of metal with as much ease as if it were box-wood. In the next machine a gun is being bored, the drill twisting its way down the fixed mass, and a dropping shower of bright chips proving how resistlessly its tooth moves on towards its appointed goal. A third machine cuts off the "dead head" of a cannon. All guns are cast in the pits in a perpendicular position, breech downwards, and are made at least one-third longer than they are intended to be when finished. The reason for this is, that the superincumbent metal forming the "dead head" of the piece may by its weight condense the portion below it which is to form the true gun--the extraordinary pressure of the powder requiring the metal to be extremely close in order to withstand the strain. Besides these lathes, which do the more ordinary work of the factory, there are what are termed exceptional machines, to finish those parts of the gun which the lathe cannot touch, such as the projecting sight, the trunnions, and that portion of the barrel which lies between them. No increase has taken place in the size of the Brass Gun Factory, although, through the energetic action of Colonel Wilmot, its produce has been doubled since the breaking out of the war: fourteen pieces of brass ordnance--six, nine, and eighteen pounders--can be turned out weekly. Brass is used for field-pieces on account of its resisting power being greater than that of iron. Experiments which have lately been made, however, tend to show that steel is a far lighter and