In a test for rapidity made by the Ordnance Department, II. S. A., 2.004 rounds were fired in 1 min. 45 sec. In a subsequent test for accuracy, out of 334 shots fired at a distance of 300 yds. at a target 12 X 26 f t., 26S hits were made. The cartridges used in the two last-named tests were solid head, containing 70 grains of powder and a bullet weighing 405 grains.
As the benefits to be gained from the accuracy, rapidity, and power of rapid-fire guns became evident from practical tests of the 3 and 6 pounders, it was seen that their sphere of utility admitted of extension, and large calibers of greater power were constructed from time to time, until the present limit of 6-in. caliber has been reached. But before any of these larger guns were ready for use, special recoil-checking arrangements, with an automatic firing position, were introduced, by means of which the loss of time from running out and relaying the gun after firing was reduced to a minimum. What limits the further extension of the system to still larger calibers is not the recoil, but the fixed ainumnition. The com bined weight of cartridge-ease, charge, and projectile should be such that one man could handle it with ease and rapidity, and could readily exert sufficient power to extract the empty cases after firing,.
The suceessfnl use of guns of this type up to a caliber of 6 in. necessitates efforts to obtain greater rapidity of the from high-power guns. and much quicker means of supplying ammunition. The next step in their development, as already pointed out by ordnance experts, lies in changing the tube, decreasing the size of the powder-chamber, and strength ening the walls of the case, all made necessary by the introduction of smokeless powders, which, with smaller charges than of present service-powders, give the same chamber press ures. but higher pressures all along the bore.
In order to cope successfully with swiftly moving torpedo-boats, a gun must be capable of giving, for a short period of time, a rapid and continuous fire of explosive projectiles, having great penetrative power up to a range of 2.000 yards, and of such quick and accurate training as to admit of being kept constantly bearing on the torpedo-boat. It was these demands that introduced the rapid-fire artillery, hut the machine guns of Gatling and Nordenfeldt, the Gardner gun, and one or two others, are still retained in service, and are considered as useful auxiliaries where there are exposed bodies of men or protection of light scantling, In these weapons the last few years have seen but slight changes, and what has been done was in the line of a positive feed, a reduction of weight, and in the fittings, rather than in any marked alteration in their mechanism. Full descriptions of all modern ordnalice will be found in the files of Engineering (London) for 1890, 1891, and 1802. See also Reports of Chief of Ordnance, U. S. A.
Ore Cooler: See Mills, Silver. Ore Drier: see Mills, Silver. Ore Roaster : see Fur naces, Roasting. Ore Smelting: see Furnaces, Smelting. Ore Washer: see Ore-dressing Machinery.