110 ANNUAL OF SCIENTIFIC DISCOVERT. 



for this gun. The range at 25° elevation was more than 4i miles. 

 The 15-inch gun, about the performance of which, at Shoebury- 

 ness, we in England know something, has been fired as follows : 

 7 times with 40 pounds of powder, and a shell weighing 350 

 pounds ; 5 times with 50 pounds of powder, and a shell weighing 

 350 pounds ; 70 times with 50 pounds of powder, and a shot 

 weighing 431: pounds; 59 times with 55 pounds of powder, and a 

 shot weighing 435 pounds ; once with 60 pounds of powder, and 

 a shot weighing 434 pounds ; once with 75 pounds of powder, 

 and a shot weighing 434 pounds ; once with 80 pounds of powder, 

 and a shot weighing 434 pounds : once with 90 pounds of powder, 

 and a shot weighing 434 pounds ; and 125 times, with 100 pounds 

 of powder, and a shot weighing 434 pounds. The mean range 

 obtained with 100 pounds of powder, at an elevation of 32°, was 

 7,732 3'ards. The mean initial velocity of the shot, with the same 

 charge, was 1,510 feet per second. Ten rounds were fired in 35 

 minutes, which was as rapidly as the gun could be fired with 100 

 pounds of powder, and a solid shot. An examination of the gun 

 has failed to detect any enlargement of the bore, from firing; 

 neither has the metal been cut away by the powder. In fact, the 

 gun is reported to be serviceable in every respect. 



If the performances of the 15-inch gun are thus proved to be in 

 every respect satisfactory, no less so are those of the 20-inch gun. 

 This formidable weapon has been fired with 200 pounds of powder, 

 and a shot weighing 1,100 pounds, the range at 25° elevation 

 being more than 4^ miles. This gun and its charge are difficult 

 things for us to realize, but here they are, and here are their 

 results, and. what is more, General Dyer has no hesitation in 

 assigning this heavy charge as that which may be regularly used 

 in this gun. — London Mechanics'' Magazine. 



ENGLISH ORDNANCE. 



At the last anniversary meeting of the British Institution of 

 Civil Engineers, Mr. C. H. Gregory, the President, delivered an 

 address, from which the following are extracts: — 



"Irrespective of breech-loading, which has been abandoned 

 in this country for heavy guns, and of rifling, in v/hich the original 

 mode has been to a great extent superseded by larger grooves to 

 guide soft metal studs fixed on a hard metal projectile, the gun 

 now generally manufactured for the service has undergone con- 

 siderable structural changes, the most material one being the 

 diminution of the number of parts, and the substitution of outer 

 coils of fibrous Staffordshire iron for coils of the best Yorkshire 

 iron, tough steel being still maintained for the lining, as best 

 resisting surface wear. In the former type of gun there was a 

 forged breech-piece over the breech end of the steel lining tube, 

 and, according to the size of the gun, a greater or less number 

 of coiled tubes, carefully and successively fitted on. The pattern 

 at present in use for all guns consists of only 4 pieces, namely, 

 1st, the steel barrel, or lining ; 2d, a coiled tube over the barrel. 



