80 ANNUAL OF SCIENTIFIC DISCOVERY. 



tured at a cost of 2, all the materials being Swedish. The manu- 

 factory employs 250 workmen, and turns out 5,000 rifles annually. 

 The Board of Ordnance of Christiana exhibited specimens of the 

 rifled musket in use in the Norwegian army, interesting from the fact 

 that breech-loading has been adopted throughout the army, and that 

 the bore is hexagonal ; this principle having been in use for some 

 considerable time. Spain, like Italy, has adopted the French system 

 of rifling in her artillery, namely, that of Treuille de Beaulieu, and 

 sent several specimens to the Exhibition. The royal foundry of 

 Trubia produces all the steel and iron, both wrought and cast, re- 

 quired for the use of the Spanish service. This foundry exhibited, as 

 a specimen of the rifled iron ordnance now adopted in the Spanish 

 service, a gun of cast iron, strengthened with bands of steel, and 

 rifled after the French model, about 10 feet 9 inches in length, and 

 weighing about 8 cwt., the diameter of the bore being 16 centimetres 

 (6^ inches). The charge for this gun is 8 pounds, and with sixteen 

 degrees of elevation it is stated to have attained a range of upwards 

 of 6,000 yards with a cylindro-conical ball of 68 pounds weight. Aus/- 

 tria, like many of the other nations of Europe, has been attracted by 

 the advantage which the French system of rifling ordnance possesses, 

 of enabling existing stores of artillery to be utilized, and has conse- 

 quently adopted that principle since the early part of 1860. No dis- 

 play, however, of ordnance was made from this country. The question 

 of the adoption of a rifled arm for the artillery of Russia is still to a 

 certain extent undecided as regards heavy guns ; but the greater pro- 

 portion of their field-artillery has been rifled upon a principle which 

 is only a slight modification of the French method. A rifled gun of 

 cast steel, in this department, bore an inscription stating that four 

 thousand rounds had been fired from it without injury. The Prus- 

 sian government have adopted the Wahrendorff principle (above 

 noticed), both as regards breech-loading and lead-coated projectiles. 



Impregnable Port-hole. In the naval department a model was 

 shown for closing the aperture of a port-hole, during the time when 

 it is unoccupied by the gun, with a revolving shield. The gun goes 

 out through a ball, or spherical revolver. This revolver moves on 

 axles, and allows the gun to be turned in every direction ; and which- 

 ever way the gun is pointed, whether elevated, depressed, or trained 

 aft and forward, there is no opening disclosed for the entry of a 

 Minie bullet. When the shot is discharged, the gun recoils, and the 

 revolver turns, and presents a closed appearance to the exterior. 



Improved Furnaces. In the Swedish department specimens of 

 iron were exhibited made with peat as fuel ; and in the Italian de- 

 partment steel was shown made in a gas-puddling furnace with the 

 same fuel. The furnace in which peat is thus made available for 

 metallurgical purposes, although not easily described without dia- 

 grams, is still so well worthy the attention of those interested in econ- 

 omizing fuel, that we make the attempt to render its structure intelli- 

 gible to the general reader. We must assume, in the first place, that 

 he is acquainted with the form and action of a common reverberatory 

 furnace such as may be seen in operation in many parts of the coun- 

 try. Instead of the usual fire-place, there is what is called the " gas 

 generator." This consists of a circular chamber of fire-brick several 



