M. Paixhans proposed as the unit the French 36-pounder. He explained the advantages to be derived from arming existing ships-of-the-line with 36-pounders all of the same calibre but of different weights on the respective decks. The guns on different decks would take different charges and would therefore project the shot with different muzzle velocities. They would be disposed, the heaviest on the lower deck; a lighter type (reamed out from 24-pounders) on the main deck; still lighter guns on the upper deck, and 36-pounder carronades on the quarter-deck and forecastle would complete the armament.
The employment of solid shot was not favoured by him, however, and he claimed the results of various trials as showing the superior offensive value of shells, when compared with solid shot. Comparing a solid shot and a shell of the same external dimensions discharged with the same muzzle velocity, the former, he said, had only the advantage in superior range and penetrative power. The latter, while having a range greater than those at which sea actions were invariably fought and sufficient penetrative power to effect a lodgment in a ship’s timbers, required less powder to propel it, a lighter and therefore more rapidly worked gun from which to discharge it, and it had a destructive effect enormously greater than that of the solid ball.
The complete proposal therefore involved the adoption of shell guns exclusively, new guns being made and old guns being reamed out as necessary to enable each ship to carry pieces of one calibre alone. The calibre proposed as unit was the long French 48-pounder. And, as an example of the way in which M. Paixhans would convert armaments, the case of the French 74-gun ship is here taken. This, with an existing armament of:—
28 36-pounders,
30 18-pounders,
14 6-pounders,
14 6-pounder carronades,
a total of 86 pieces throwing 2250 pounds of solid shot, he would convert into a ship armed with:—
28 48-pounders (reamed from 36-pounders),
30 48-pounders (of same weight as 18-pounders),
28 48-pounder carronades;
eighty-six pieces throwing 3010 pounds of charged shell weighing 35 pounds each.
For the new shell gun he proposed a design of iron howitzer in which the distribution of metal was so adjusted as to give a sufficient factor of safety at every section, while at the same time allowing the total weight of the piece to be reduced to a minimum. This canon-à-bombe was to be mounted on a stable form of carriage, made without trucks but fitted with running-out rollers and directing bars to control the line of fire and the direction of recoil.
To those who were inclined to regard with feelings of horror this new use of explosive missiles, this progress in the art of destruction, the inventor put the question, whether experience had not proved that the perfection of arms had not had the effect of making warfare actually less bloody; whether it was not a fact worth consideration, that, while in days of old the destruction and loss of life in battles was enormous, the loss of English seamen by gunfire in the numerous combats of three long and bitter wars of recent times amounted to less than five thousand killed. And would not, therefore, further development of arms be a positive benefit to humanity?[106]
One other feature was put forward to complete this scheme of re-armament, the importance of which it is unnecessary to emphasize. M. Paixhans explored the possibility, by the sacrifice of a tier or more of guns, of rendering all classes of ships invulnerable by casing their sides with iron plates. Although rejected at the time, and as the result of trials which he himself carried out, this suggestion was destined to be carried into effect in startling fashion some thirty years later: with what consequences to naval architecture we shall presently see. In connection with the scheme of re-armament outlined by M. Paixhans in 1822 the suggestion was important in that there was implied in it an admission of one of the two weak features of the inventor’s system. The shell gun would lose its superiority over the shot gun, and might indeed be reduced to absolute impotence if, in imitation of France, the enemy also cased his ships of war with iron. The solid shot gun would once again have the advantage; in fact, that very equilibrium of relative values which M. Paixhans was endeavouring to destroy would once more obtain between the navies of the two rival powers.