The Gun-carriage Department has workshops both for metal and wood work, and each branch contains many subdivisions. There is nothing, however, in this department which is peculiar to the Arsenal, with the exception, of course, of the special articles which are manufactured; that is to say, forging, steam-carpentering, wheel-making, and so on, are carried out as they would be executed elsewhere. The guides always make a point of showing the wheel-shoeing pit, as it is called, in which the tyre is put on a gun-wheel. The machinery in this department is very complete, especially in the carpenters' shops, where the lathes which work automatically, and turn wheel-spokes and such things according to a given pattern, and the steam-saws for cutting dovetails for sides of boxes, and other machinery, are all constructed on highly ingenious principles. With regard to the articles constructed, the trail of a gun may be followed in all stages of its construction until it appears complete with its wheels, and ready for the gun to be placed on it. Here, too, may be seen the ingenious Moncrieff gun-carriage, by which the gun is only raised above a fortification at the moment when it is fired, the 'sighting' being done from below by an arrangement of mirrors. The Stores, again, are remarkable only for the quantity of material stowed away ready for use. For instance, there are ten thousand complete sets of harness for guns and baggage wagons always kept in stock. But when the visitor has just walked once through these storehouses, he will probably have seen all that he cares to see there. It is, however, when we come to the Gun Factory that the special interest of the Arsenal begins. Imagine a huge mass of steel welded--for casting would not give sufficient strength--into the form of the trunk of a large fir-tree, and you have the first stage of a gun's existence. This solid mass is to form the tube of a cannon, and the solid core has to be removed by ingenious and powerful machinery. It takes a week or two to bore the interior of some of the larger guns. Some of the machines are constructed to bore a hole which is continually enlarged by successive tools; while others actually cut out a round solid mass from the interior. The tube has also to be subjected to the process of being turned both within and without, and it is then fit for the next process, which is that of cutting the grooves within it which give the required spin to the projectile, commonly called rifling. This is a delicate and intricate process, for the utility of the gun of course depends largely on the accuracy with which the grooves are made. The actual cutting is performed by a machine which travels up the tube at the required spiral; but as the work proceeds, the man in charge carefully examines the grooves along their whole length with the aid of a candle fixed at the end of a long rod which he pushes up the tube.