PARROTT, RODMAN, AND DAHLGREN GUNS 503 dered by the Government, and made at the West Point Foundry. The first gun on this principle, the essential feature of which is the reinforcing or strengthening the breech of a cast-iron gun by shrinking upon it a wrought-iron jacket or band, having a definite strength and position proportioned to the size of a gun, was made in 1860, and patented in October, 1861. During that year Mr. Parrott also received two patents for projectiles for Rifled Cannon, which were designed as an accompaniment of the guns, to the neglect in using which he in great part ascribes the bursting of several of the large Parrott guns at Fort Fisher, by the premature explosion of shells within the guns. Later, in the same year, he took out another for an improved mode of applying fuses to shells, whereby they became either time or percussion fuses. These projectiles have been successfully used of the weight of six hundred pounds. An additional patent for an improvement in hooped ordnance, was granted Mr. Parrott in 1862, by which time he began to construct, in the same way, rifled cannon of eight inch calibre, or two hundred pounders, which were mounted at Yorktown, and commended themselves to the approbation of American and foreign artillerists by their performance, as those of less calibre had done before. Two ten inch three hundred pounders, afterward constructed, were disabled from the cause above named, but of other sizes, as thirty pounders and upward, and of the projectiles, the value was abundantly tested in the bombardments of Forts Sumter, Macon, Pulaski, and the shelling of Charleston, where they were chiefly used as siege guns, often at a distance of four thousand yards and upward. Parrott rifled guns of large calibre are used upon United States naval vessels, being able to throw projectiles with greater accuracy and to a greater distance than smooth bore guns. To prevent the bursting of shells within the bore, by friction of the powder within them, on the discharge of the gun, Mr. Parrott successfully adopted the plan of coating the interior walls of the shell with a lacker or varnish of rosin, tallow, and brown soap melted together. The Rodman gun, while having in some respects a peculiar form, is chiefly distinguished for the mode of manufacture proposed by Lieutenant Rodman, while superintending the casting of eight inch cannon for the United States Government at the Fort Pitt Foundry, in 1845, and, after satisfactory tests, adopted by the War Department, in the casting of all heavy ordnance. It consists in making the casting around a hollow core or core-barrel, as it is termed, into which is introduced a copious stream of cold water, while the outside is kept heated, until the mass of metal is cooled from the interior. This mode of cooling is thought to possess two advantages over the old one 504 IMPORTANT INVENTIONS FROM 1850 To 1860. of casting solid and then boring out; first, in reversing the strain on the metal, making it less liable to burst; and, secondly, in giving greater hardness to the internal surface of the gun, making it less liable to abrasion by the friction of the projectile, and the action of the gases generated by the burning powder. It has been deemed the only effective way of making cast-iron guns of large calibre. The gun of Rear-Admiral Dahlgren is distinguished principally by its exterior form. To obviate the contraction consequent on cooling a solid casting of large size from the outside, his castings were made considerably larger than required when finished, and, after cooling, were annealed and turned down to the proper size and shape. The Dahlgren and Rodman guns were generally smooth bore, though some large ones were rifled. Heavy cast-iron rifled ordnance, however, made by any of these modes, has by no means proved a success, the ordinary tests of the proving ground falling short of that to which guns are subjected by rapid and continued firing in battle, where many of them have burst, with disastrous and mortifying results. The Steel Rifled Cannon is altogether a product of the late war. It was invented and patented by Mr. Norman Wiard, of the Trenton Wiard Ordnance Works, whose contributions in guns, and materials of war manufactured by him, amounted to four and a half millions of dollars, and the cost of experiments on guns to four hundred thousand dollars of his own means, directly expended. Long and favorably known throughout the western country before the war as an intelligent and practical machinist, he at the very commencement of the war turned his engineering abilities and experience as a manufacturer to the service of his country, in the invention and construction of ordnance and other materials of war. As early as May, 1861, he contracted with General D. E. Sickles to furnish three batteries of steel rifled guns for the Excelsior Brigade, which, with the carriages, implements, stores, etc., were completed, inspected, and ready for service on the 4th of July. They were the first steel guns ever made in the United States, and were from original designs by Mr. Wiard, who endeavored to discover and avoid the causes of frequent failure in heavy ordnance. He succeeded in producing guns unrivalled in precision and range, if not also in their powers of endurance. The carriages for these guns were also of new design by the manufacturer, and were the first ever built expressly adapted for rifled cannon, being constructed to give the gun its utmost range without a special adjustment of the carriage. The superiority of these guns as field artillery will not probably be questioned. Mr. Wiard soon after began to construct heavy steel rifled guns for the navy. The blocks of steel from which some of these were made in 1861, weighed WIARD'S GUNS-THE AMES GUN. 505 eight thousand pounds each, being the largest masses of steel, it is Although the steel was of suguns fourfold that of cast-iron believed, ever made up to that time. perior quality, and the strength of the cannon of the same calibre, three of them, made from Government patterns, afterward exploded on the ninth round, after rapid firing in cold weather. Mr. Wiard's metallurgic experience at once suggested the cause, and the remedy, which was a very simple one, to counteract the effects of unequal expansion, but his proposal was not entertained by the Ordnance Department, and his offer to construct new guns designed to obviate the effects of rapid firing upon all heavy ordnance met with the same fate. Having, by a series of costly experiments, satisfied himself of the correctness of his theory, which had long employed his research in connection with steam boiler explosions, Mr. Wiard has given to the world, in different forms of publications, the result of his investigations, which may be profitably studied by scientific and practical men, in relation to this important and still mooted question. In 1862, Mr. Wiard supplied, of his own manufacture, the entire armament, guns, ordnance stores, and equipments of the expedition commanded by General Burnside, to whose entire satisfaction it was fitted out. About the same time he was commissioned to finish a large number of seven and a half inch one hundred and fifty pounder rifled guns, of the Dahlgren pattern, from blocks cast at West Point and Pittsburg, weighing twenty-three thousand pounds each, in the rough. But the order was suspended by the bursting of most of them in remarkable confirmation of his repeated predictions and representations to the Government, as to the defective principle on which, in common with other large guns, they were constructed. This defect in the system of making heavy ordnance as well as the remedy Mr. Wiard claims to have been the first to discover, and he complains that either from interested motives or an undue attachment to effete methods with great detriment to the public service, he has not been permitted to bring into practical use a better plan. By arrangement with the Secretary of the Navy, a large navy gun was constructed in 1864, at a cost of eighty thousand dollars, which has ever since been awaiting at the Works in Trenton, an order for its trial, while the Government is selling for old iron, at a hundredth part of their cost, the old guns and substituting none in their place. In view of the general failure of heavy ordnance, and of Mr. Wiard's large experience and great facilities for manufacturing both rifled and smooth bore guns of the largest size, it might have been expected, that his best and most practical proposals for turning to account the vast amount of the best material accumulated in the Government arsenals and navy yards as worthless guns, would have |