It was not for some little time after the adoption of the 303 that the labours of Nobel, supplemented by those of Sir Frederick Abel and others, produced the smokeless explosive known as cordite, which has ever since been used in the cartridges made for the Government arm. The developement of smokeless powders is a special subject which does not fall within the scheme of the present work. They are much more powerful, weight for weight, than black powder. For instance, the charge of cordite for the 303 rifle weighs from 30 to 31 grains, but is equivalent in propelling power to the old charge of 85 grains of black powder used in the MartiniHenry rifle. Smokeless powder, too, is much smaller in bulk, and whereas the cartridge would contain no more than 70 grains of black powder, even when heavily compressed into a pellet, the much more powerful charge of cordite leaves a very considerable air space behind the bullet. The use of smokeless powder, and of compound bullets with a hard envelope usually either of a mixture of nickel and copper, as in the British rifle, or of steel faced with a thin plate of nickel, is general in the military arms of the present day. The principle, however, on which the bullet is fitted to the grooving is practically a revival of that which Robins mentions in the passage already quoted, that by which the bullet being of more than the full size of the bore is by the explosion forced into the grooving. The 303 rifle has grooves about 005 inch deep, so that the extreme measurement of the circle including the depth of the grooves, is 303+005+005, or 313 inch, and the diameter of the bullet before it is fired measures 311 inch. The pressure of the explosion forces it into the barrel under heavy stress, and it is effectually fitted to the grooving, so that the gases are sealed from escaping past it. So complete is the sealing when this principle is properly carried out that with most modern rifles of this class there seems little or no advantage in interposing a wad between the powder and the bullet. It will thus be seen that the principle of the expanding bullet, upon which so much care and invention was bestowed, and which solved the problem of accuracy and rapid loading

in muzzle-loader and breech-loader, has been entirely departed from in the new class of military weapons.

One difficulty connected with the bullet gave some little trouble at first. The heat set up by the friction of the bullet on the bore is very considerable. It was found with the experimental ammunition first made for the 303 that the first shot fired from a clean barrel was never seen or heard of again, while, when once the barrel had been fouled, the rifle shot satisfactorily. The only reason was that the friction of the bullet in being passed up the barrel developed heat enough to melt that part of the leaden core which lay next to it. Apparently the deposit from a shot previously fired was sufficient to reduce this heating effect. The difficulty was so great that it had to be got over by thickening the metal envelope of the bullet. It could equally have been overcome, as Sir Henry Halford pointed out in a lecture delivered at Aldershot at the time, by inserting a minute layer of some non-conducting material between the leaden core and the metal thimble. Some years ago the writer was trying a series of experiments with various loads of different smokeless powders, and a bullet of normal make which gave no trouble. In testing one particular powder at the ballistic pendulum the shooting was found to be extremely wild. On firing a series of shots through a cardboard target at a distance of only 4 or 5 yards, the reason became evident. Most of the shot holes were seen to be surrounded by one or more little black cloudy marks, sometimes showing a spiral inclination, which proved clearly enough that a spattering of very fine particles of melted lead was escaping from the base of the bullet as it flew. Why the conditions of friction with the deposit of this powder were so different from those of all other powders used with the same bullet, it would be very hard to say. Mr. Metford, in investigating the vagaries of the first shot, had been able to see the bullet in the air surrounded, as it flew, by a little cloud of melted lead consisting of particles so fine that on recovering the bullet, and weighing it, it was found to have lost only one or two grains in weight during a flight of several yards through the air. He found that if the barrel had been