Page:Popular Science Monthly Volume 11.djvu/621

Rh the Vienna arsenal is engaged in the manufacture of heavy guns of the same character. Never was a more energetic step taken. A new cannon of some sort was held to be absolutely necessary to uphold the prestige of the army, and a commission having been intrusted with the selection of an arm, pronounced without delay in favor of the scheme brought forward by General von Uchatius. In October, 1874, the first round was fired from a Uchatius gun, and a twelvemonth afterward the sweeping reform which was to introduce an entirely new artillery throughout the Austrian service was decided upon. Government sanctioned an expenditure of £1,800,000 to be spent in two years, and General von Uchatius was directed to give all the assistance in his power toward the fulfillment of the design.

The Uchatius gun is made of so-called steel-bronze. Chilled bronze would be a better name, since Uchatius casts his metal in a chilled, or metal mould, in the same manner, pretty well, as Sir William Palliser produces his famous chilled projectiles. Bronze, as everybody knows, has been a favorite metal with gun-founders from the earliest days, and in the East, especially, magnificent castings of this nature have been produced. About ninety per cent, of copper and ten of tin is the mixture commonly employed in making ordinary bronze, and eight per cent, of tin is the proportion preferred by Uchatius. The difficulty in casting bronze, as those who have any experience know full well, is that of securing homogeneity, soft particles of tin becoming isolated in the mass, and giving rise to the defect known as "tin-pitting." Whether we have lost the secret of bronze-casting, or whether in former times they were more skillful at the work, certain it is that founders of the present day are unable to secure so uniform an alloy as formerly. This was very apparent when some eight or ten years ago our own, Government adopted, for a brief time, bronze artillery. The addition of a small percentage of phosphorus did not mend matters, and the highest authorities on the subject were at a loss to suggest an effective remedy. Our bronze guns, too, had another defect which could not be overcome. After firing the bore became affected, and the weapon, as it was termed, "drooped at the muzzle." These were the two defects indeed that led mainly to the abandonment of the bronze gun in this country, and they are, too, the difficulties which General von Uchatius appears to have overcome. He has got rid of "tin-pitting," and his guns do not "droop at the muzzle."

Uchatius found that by subjecting the alloy in a liquid form to considerable pressure, he was enabled to secure a perfectly homogeneous mass, a result which was also furnished, he discovered, when he had gone a step further, if the molten metal was rapidly cooled. Steel-bronze is apparently made much in the same way as the toughened glass of which we have heard so much lately. After being cast in a mould, the alloy is thrust into a reservoir of oil, heated to a high temperature, so that the metal suddenly cools, but only down to a