The diversity of cutting-tools in these different machines strikes the observer with astonishment; the oddest shapes, the most unlikely-looking forms, proving admirably adapted for the purposes they are intended to accomplish. Many of these work automatically--that is, they engage and disengage themselves; setting to work only when they are fed with material, and, when their rodent-like teeth have gnawed away as much metal as is requisite, they stop of their own accord. The effect of this is so extraordinary, that it almost seems as if those bright limbs of iron, which stop and move on without human agency, must be directed by some sort of metallic brain. The most common form of tool employed is what is termed the circular cutter or milling-tool, which is constructed to fit every class of work. These cutters will continue serviceable for months without requiring to be sharpened, in consequence of each being restricted to its own limited sphere. The amount of thought employed in the construction of many of these machines must have been immense, and when they were completed, two-thirds of the manufacturing difficulty was overcome, and the musket more than half made. A most ingenious machine, the parent of a numerous progeny, was, many years ago, invented by an Englishman, and applied to copying the fine lines of statuary, and transferring them to ivory and other materials. The applicability of this instrument to the production of the irregular forms in the gun trade was first perceived by our cousins across the Atlantic, and for many years they have employed it for the rapid and true production of many parts of the musket, whilst our own manufacturers in London and Birmingham have been content to execute the same work, laboriously and expensively, by hand labour. The copying machines now at Enfield have been imported direct from America. They are principally employed in fashioning gun-stocks. They convert the rough slabs of walnut-wood, just outlined in the proper form, which come from France, Belgium and Italy, into the finished article, with all its grooves, holes, and beddings for lock and barrel. This extraordinary apparatus may be said to work with two hands: the one feeling the outline of the pattern to be copied, the other directing a tool uniformly with it and cutting the object to the required form. Let us, for example, take the machine that hollows out the lock-bedding in the stock. Not only are the outlines of the most irregular form, but they are sunk to three different levels, and it would almost seem impossible that a machine should excavate so complex a bedding with minute accuracy. Nevertheless, it is done in a few minutes by an apparatus, which revolves and brings, one after the other, some new tool into play according to the work to be done. Whilst the operation is going on, a little blower clears out the chips as cleverly as though the machine had human breath. The different portions of