Put on a barrel, from the breech end to the muzzle, a number of rings of lead; be sure you have them tight, and not further apart than three or four inches; fire that barrel with a usual charge, and if it be a correct taper for shooting, it will have expanded the whole of the rings an equal distance. From the observations already made, the reader will perceive that the shooting of all barrels depends on a certain degree of friction. The degree of friction necessary, varies according to the nature and substance of the metal. Those metals that require least shoot best. The object of the friction is to create a greater force, by detaining the charge longer in the barrel. If, then, there should not be an extra quantity of powder to consume, the friction would be a decided evil. This may be understood by rifle practice, in which we find that a short barrel of eighteen inches, with a certain charge, will throw a ball as straight, and quite as strong, or stronger, than a barrel of three feet, loaded with a similar charge. I account for this fact thus: the barrel of eighteen inches will burn all the powder put into it; the long one can do no more. As soon as the ball has left the short barrel, it meets with no impediment but the air. By the time the ball in the longer one has travelled eighteen inches the powder is all consumed; the volume of air in the remaining eighteen inches acts as a destroyer of the force given to it, and it naturally drops its ball short of the other. Increase the charge of powder to as much as the long one can burn, and then it will throw its shot to nearly twice the distance of the other. An addition of powder beyond the quantity the barrel can consume is disadvantageous; the reverse will be found equally so. Thus it is with fowling-pieces. The quantity of powder that a gun would burn in the shape of a cylinder, would be too little, when, by altering that shape, you increase the friction. The quantity must, therefore, be increased, or this friction will diminish the force of the shot. It is on this that the mistaken supposition is founded, that short barrels will shoot as far as long ones. It is true that with a small charge, or very fine powder, the short barrel will kill at the distance of thirty yards, as well as the long one; but put in the long one as much powder as it can consume, then try the two at twice the distance, and you will find out the mistake under which you have been labouring.