For this reason, presumably, and because the shell gun system contained, though in a less degree, the disability inherent in the carronade system—inferior ranging power, enabling a clever opponent armed with long solid shot guns to fight at a range which was too great for shell—the Paixhans scheme was not adopted in its entirety by the French government of the time. But the principle of unity of calibre was acclaimed and approved almost immediately, applied to solid shot guns. The French 30-pounder was chosen as the unit. In 1829 guns of this calibre, made on several different models to suit the various decks and classes of ship, were mounted in their fleets.[107]
In the meantime M. Paixhans had made further progress toward perfecting the details of his shell gun system. A canon-obusier of 80 pounds was made to his design, a chambered howitzer of the same weight (about 72 hundredweight) as the French 36-pounder truck gun and of 22 centimetres calibre. This was designed to project a hollow shell of the same size as the French 80-pound solid shot, but weighing, when its cavity was filled with a charge of 4 pounds of powder, 56 pounds French (62½ pounds English). The shell gun itself was of a distinctive shape. The characteristics of short chase, large bore, a chamber, a small propelling charge, and a scientific elimination of all useless metal, resulted in a form of ordnance quite different from that of the long-accepted smooth-bore cannon. It was easily recognizable by its straight muzzle, smooth lines and the absence of the usual ornaments and reinforcing rings. When, eventually, the New Arm was adopted by other powers, their shell guns too, though independently evolved, were found to exhibit the same external features: the features of what came to be known universally as a “Paixhans gun.”
The terrific effect of charged shell, fired from this form of gun with sufficient velocity to find a lodgment in a ship’s timbers, was demonstrated at Brest in 1821 and 1824; in the latter trials the target being a frigate, the Pacificateur, moored in the roadstead. High range and accurate shooting were obtained. The incendiary effect of the shell was prodigious: so impressive, indeed, that in spite of a strong opinion in the French navy against further carriage of bombs in ships-of-the-line, the Commission recommended “that canons-à-bombe be adopted, even in ships-of-the-line, but in small numbers.”
But though the principle of the shell gun was accepted by experts, public opinion was not yet ready for the change. The Commission had shown a sage circumspection in regard to the extent of the change proposed; but public opinion was not yet satisfied that the new arm was sufficiently safe. The scheme suffered a long postponement. In the meantime several further trials were held. The design of the piece was again modified; a larger chamber was arranged and a support was cast, at the commencement of the chase, for carrying a sight. Tests à outrance were made to find what maximum charge such a shell gun would safely stand; and at last, in 1837, the principle of shell fire was accepted by the government, the Paixhans gun being assigned a place in the prescribed armament of the fleets of France. To the impairment of the unity-of-calibre principle, lately achieved, shell guns of 22 centimetres were admitted as part-armament of ships the greater number of whose pieces were 30-pounders firing solid shot.
A PAIXHANS GUN
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In England the arguments in favour of a new and more scientific adjustment of ship armament had not until this date been clearly formulated. Of the tendency to a single calibre there certainly had been many demonstrations in the last decades of the eighteenth century: a tendency favoured by the replacement of the smaller long guns of the fleet by carronades. Sir Howard Douglas, in his Naval Gunnery, the first edition of which was published in 1820, had demonstrated the advantages of large calibre, the inefficiency of random broadsides, and the high importance of the deliberate aim of single guns. And in 1825, before the French began to remodel their ordnance, Colonel Munro, of the Royal Artillery, submitted his project to the naval authorities of arming our ships solely with 32-pounders, of different classes and weights to suit the various circumstances. But no radical revision of armament was made in the British navy until some years after the French had made the great stride of 1829, already described.
Unity of calibre, then, was no novel idea on the part of M. Paixhans. “No project,” says Dahlgren—“no project has proved more attractive to naval men than that of having a uniform calibre throughout the entire fleet. It has been proposed from time to time without success, until adopted for the French navy in 1829.
“In the promptness with which the example was followed by England and the United States, may be recognized the general convictions of the profession in regard to the serious mischief inseparable from the chaos of calibres that prevailed, and the urgent necessity for some measure that would simplify the complex economy of naval ordnance.