56 TEAR-BOOK OF FACTS. 



charge, amounting to 12 lbs. of powder, was fully ignited just at the 

 moment the shell was in the act of leaving the muzzle of the gun. It 

 could, therefore, only be a question of time whether the shell burst 

 within or outside the gun. If the shell burst within the muzzle of 

 the gun, the destruction of the gun followed as a matter of course. 

 Directly this failure in the manufacture of the shells was discovered, 

 steps were taken to rectify it. Instead of being made of two pieces, 

 the shells were now constructed of one piece of iron, and the muzzle 

 of the gun had been strengthened by the addition of a ring of 

 wrought iron. Should, therefore, any of the old store of shells be 

 used by any chance, the gun would be strong enough to resist the 

 contingency. It was found that these guns were now thoroughly 

 equal to the requirements of the service. 



THE NTCTOSCOPE. 



Sir "W. Armstrong ha3 described to the Institution of Civil 

 Engineers the principle of the Nyctoscope, an ingenious instrument 

 designed by him for enabling the gunners to maintain a fire upon any 

 given object after nightfall. The principle of the instrument is t? 

 render a false object in the rear, or at one side, visible upon a ver- 

 tical line in a mirror, when the gun is laid upon the true object. 

 A lamp attached at night to the false object becomes visible upon the 

 same mark in the mirror, when the gun is in line with the true 

 object. The vertical adjustment for elevation is effected by a 

 spirit-level clinometer, forming part of the instrument. 



KRUPP'S GERMAN CAST-STEEL GUN. 



From a Report made to the Prussian Government by Colonel 

 Orges, it appears that this German Cast-steel Gun has given the 

 most satisfactory results, as regards strength. A bar of one inch 

 square of this material has borne a weight of 50tons, whereas a bar of 

 wrought iron of the same dimensions broke with 33 t<>ns. Mr. Krnpp's 

 gun bore five anil a-half times the internal pressure of an ordinary 

 cast-iron gun of the same internal and external diameters, ami three 

 times the internal pressure which burst a bronze cylinder of the same 

 dimensions. Mr. Krupp is now making three hundred guns fur the 

 Prussian Government. The weight of his 12-pounder breech-loading 

 gun was 825 lbs. The cost of the forging was about '.'•"/., and that 

 of the gun complete was 1501. These statements have been made 

 by Mr. C. W. Siemens, C.E. 



BUF.F.CH-I.OADING R1FI1-. 



Mr. W. Strode lias exhibited and explained to the Institution of 

 Civil Engineers specimens of Messrs. McKenzie and Wentworth's. 



Breech-loading Hides. 



The conditions sought to be fulfilled in these rifles are : — 



1st. That tlioy should '"■ ibfa to take tl" - present ammunition. 

 -ncl. Thai they ahonld hare a sound joint at the junction of the breeoh and tho 

 barrel. 



Phal there should be nothing liable to be discharged against the soldier 

 own act, in case of bursting; and, therefore, no plug or atopper 

 y>ut iu lrum tho bnck.ur breeoh*end of the barrel, 



