April 6, 1861; The Scientific American
At this time public attention is considerably interested in all that relates to the art of war. We have kept our readers pretty well supplied with intellectual munitions of this sort, and we believe many of them will be much interested in the following report of a lecture recently delivered in this city by Capt. Mansfield Lovell, late of the City Guard, on “Heavy Ordnance and Seacoast Defenses.”
Captain Lovell commenced by remarking that it was impossible to go much into the details of his subject in the brief time proper for a lecture; but he intended to avoid technical terms, and, in plain talk, to give some general ideas, leaving particulars to be sought in books by those who wanted the facts. Heavy ordnance comprised four kinds of destructive means: guns, howitzers, columbiads and mortars. Their respective spheres of service were: seacoast, field, garrison and battery. “Caliber” meant the diameter of the bore of a gun, and not the weight. A 10-inch mortar, charged with 3 ½ lbs, of powder, would throw a shell 1 mile in about 19 seconds. There was a great deal of uncertainty about the fuses, however, especially in water, and much attention was devoted by experienced gunners to insure the burning of the fuse, so that it could be relied on in calculations of time and distance. Ricochetting shots were thrown at a slight elevation, and intended, by their irregular and bounding course, to break away opposing obstacles of the enemy. Columbiads were the guns of the present day, and were used both for solid shot and shell. The various patterns and forces of this gun were described. Mortars were used for reaching out-of-the-way places. At the siege of Monterey, the Mexicans gathered within the city in the plaza, and one shell thrown among them killed 26 men. The effective range of 22-pound guns was about a mile. The capacity of a gun to impel a projectile 3 or 4 miles did not make it serviceable at that distance. A mile was about the longest range for destruction.
The Captain gave accounts of attempts to cast very large guns. The difficulty was in casting the iron. Captains Rodman and Dahlgren, the very best American gunners, were experimenting upon the plan of cooling the inside part of the cannon first, which was done by casting it with a core and letting water wash through the opening, keeping the outside hot meanwhile. The old mode, and which is yet followed, is to cast the cannon solid and bore it after cooling. In casting very large guns in this way, too much expansion was given to the iron in cooling to make them strong in proportion to the size. At Fort Monroe, successful experiments were being made with a gun 16 feet long, and weighing 25 tons. It was designed to carry a ball of from 305 to 401 lbs., requiring a charge of 35 to 40lbs. of powder. It was found that such a quantity of powder was too powerful for the iron, but very large grained and easily compressed powder, which would create gas less instantaneously than the flue material, acted satisfactorily. By this means, the projectile was moved and helped on its journey through the bore, instead of the shock being all expended in one prodigious blast, that would tear away whatever opposed it, and was not strong enough to resist its stupendous power.
He gave an idea of the caliber of shells by stating that a 20-inch one would weigh 1,000 lbs., and a 30-inch one 3,000 or 4,000 lbs., or sufficiently large to crush a large ship so badly as to sink her at once. After referring to the power of the Armstrong gun, he interested the audience a good deal by describing the effect of shot. A shot did not make a hole of its own size right through wood, but indented it, the fibers springing back after the shock. Generally the course of shot could only be traced by a wire, sometimes by a hole as large as a man’s finger. The damage most often happened in the inside of a vessel, in splintering and breaking the wood, after the main force of the shot was spent. Forts Hamilton and Richmond, which are about a mile apart, with a vessel lying between them, could not, with their guns, send shot through two feet of its timber. There was rarely an instance where a ship was sunk by solid shot. Hot shot and shells did the mischief; the latter would sometimes make apertures of several feet in extent, through the sides of vessels. He mentioned several instances where vessels had gone through hours of cannonade and came off unsunk. The latest was that of the Agamemnon, which was under the fire of a Russian battery, at the distance of 800 yards, for five hours, without being sunk or having her engines or her batteries damaged, and lost only 29 men, although an enormous quantity of shot was thrown into her. The Emperor Napoleon had built a war vessel with sides covered with steel five inches thick. The speaker believed this vessel would prove to be invulnerable to the present class of guns, as Armstrong, whose guns had carried shot 5 ½ miles, had been unable to drive a shot through the steel coating at a greater distance than 200 yards. He thought that against such vessels the guns about our harbor could play away without effective damage. The Fort Monroe big gun, however, might crush the steel all up.
He then gave considerable attention to the weakness of the American service in respect to artillerists. The remedy rested with the people. In New York, men could readily be found to go into the forts for service, in case of an emergency; but while they would be getting ready to fire, the enemy’s vessels would get beyond reach of the guns. Raw men at the guns would take as long to fire once as practiced gunners would to fire 40 times. He said the City Guard and the Ninth and Fifth Regiments had commenced the practice of gunnery, but it was found to be pretty expensive to go to the forts to practice with great guns. The General Government had signified a willingness to make Castle Garden a practice school, with instructors, if the State would give it up for that use, but it had been found preferable to make it an emigrant depot.