If ranges of 2,000 yards and upwards are required, rifled cannon will again take their proper place; for on investigating the tables of practice published by General Jacob, I find the average distance of shot from the centre of butt to be, at 2,000 yards, nearly 9 feet, with 13·7 degrees elevation; whilst the Whitworth is said to be 11-1/2 feet, with about 8 degrees of elevation. I saw, some time ago, some practice at Shoeburyness with an 18-pounder rifle cannon, which gave a range of 3,650 yards, with an elevation of 0·10-3/4 degrees, and a breeze blowing across, a mean deflection of only 30 inches from the centre. This throws Jacob, Whitworth, and the Enfield all into the shade together; yet there can be no doubt that this can be excelled, when heavier guns are brought to the same state of perfection as this 18-pounder. The case therefore stands thus: the Jacob rifle has a greater range than the Enfield, at a cost of 100 per cent. more friction, and an expenditure of 50 per cent. more of projectile force; the Whitworth has also a greater range, but at a cost of 300 per cent. more friction, and 100 per cent. additional projectile force. With these observations I leave this subject in the hands of the public, being convinced that projectile power obtained at such a cost will never come into general use; though the production of the Whitworth rifle will always be looked upon as an experiment of very great interest. There is but one other point relating to the use of guns on such a principle, and that is their safety; which is always of the greatest importance. It is a well-known fact that the first movement of projectiles depends very much on the amount of inertia in that projectile; and different forms of projectiles, though of the same weight, will offer very different amounts of resistance to motion. No one can doubt that two columns of lead, each of an ounce in weight, one being as high again as the other, will offer different amounts of resistance; first, from the law that the time occupied in overcoming inertia is in proportion to the length of that body; secondly, if these columns of metals are confined in tubes, then the friction on the one which is half an inch long will be much less than on the other, which is one inch in length: and this is, on the mildest terms, the relative position of the two. There can be no doubt that a much greater pressure is required to start the longer column of double the length; but when we consider that there are the facets of six angles, with a spiral inclination of one in nineteen, the difficulty of starting this bullet becomes still more apparent. Now suppose the gun has been loaded a few hours, and a certain amount of adhesion has been effected between the bullet and sides of the barrel, by the unctuous deposit from previous discharges, then the difficulty of starting the bullet instantaneously will be still more increased: supposing the breech end of a barrel, with