The endeavour to produce breech-loading cannon is an effort to obtain uncalled-for and superfluous facility in gunnery; and if a perfect breech-loading cannon could possibly be produced, what would it avail? What superior property could it possess over the solid gun? It could not be safety; for when we consider the very limited number of explosions by which the very best guns are destroyed, it can scarcely be possible for a gun composed of many parts to endure the intense vibrations to which large cannon are subjected. The regular distribution of vibrations in the metal of the gun is the great point to be attended to in the construction of artillery; so that vibrations may not be incorrectly induced by malformation, or by an excess or deficiency of metal at any particular point; for where the waves of vibration are checked by an unequal distribution of metal, or other causes, there the weak point in a gun is always found, as all fractured guns clearly demonstrate. An intimate acquaintance with the metallurgy of cannon, enables me to give an almost unerring opinion as to the causes leading to the fracture. Most undoubtedly, vibration, if judiciously distributed, is the soul of endurance; but if injudiciously distributed is certain to result in the destruction of the cannon. In structures composed necessarily of many joints, obstruction to the waves of vibration must occur; the different parts do not expand and vibrate equally; a kind of revulsion is induced; part repels part, and destruction ensues as a natural consequence. Under no circumstances, therefore, can a breech-loader be as safe as a solid gun. The facility with which breech-loaders can be charged is generally trumpeted forth to the world as an advantage of vital importance; but let us carefully examine this point and see if it has not been exaggerated--whether, in fact, a solid gun cannot be charged and discharged as rapidly as a breech-loader. In the first place, all guns recoil; this necessitates the relaying of the gun after every discharge, in order to obtain accuracy of aim; and if facility of loading is to be obtained at the expense of aim, it can scarcely be called an advantage. Aim consumes more time than loading. A six-pounder may be loaded and fired six times in the first minute; but it would be impossible to do this and re-lay the gun after each shot. Where then is the advantage of firing six shots per minute if you cannot hit six objects? And if breech-loaders could be fired _sixty_ times per minute, what would they avail if aim was wanting? The raising or depressing of the breech of a gun by means of the elevating screw; slewing to the right or left, spunging the gun, and ramming home the powder and shot, all consume time; hence we think that quickness of loading is worthless.