MECHANICS AND USEFUL ARTS. 89 



and consists of nine, ten, and eleven inch shell-guns, of great weight and 

 range. The introduction of these shell-guns to the exclusion of shot, says 

 the Secretary of the Xavy, in his last report, was by no means inconsiderately 

 or hastily made. It was suggested by Commander Dahlgren, in 1850, that 

 he could " exercise a greater amount of ordnance power with a given weir/lit of 

 metal, and with more safety to those who managed the gun, than any other 

 piece then known of like, iceujJit." 



Commodore "Warrington, then at the head of the Biircau of Ordnance, 

 ordered the gun proposed. 



The proving and testing continued during the years 1852, 1853 and 1854. 

 The points of endurance and accuracy were specially examined. The first 

 gun stood five hundred rounds with shell and five hundred with shot, with- 

 out bursting, and subsequently other guns were proved to the extreme, and 

 endured 1,600 and 1,700 rounds without bursting. Shells have been adopted 

 because they are deemed preferable, not because of any apprehension that 

 shot cannot be used in these guns with perfect security, that point being set- 

 tled by actual experiment. This fact is said to be attributable to the circum- 

 stance of there being thrown into the breech a very considerable additional 

 weight of metal. If, therefore, it is at any time contemplated to attack the 

 solid masonry of fortifications several feet in thickness, solid shot can be 

 used, although recent developments in the late European wars will hardly 

 encourage such assaults to be often undertaken. 



During the past year the sloop-of-war Plymouth, under the charge of Com. 

 Dahlgren, was ordered to cruise at sea, with a view of testing the efficiency 

 and working of the new ordnance. The battery of the sloop consisted of one 

 pivot-gun, and several nine-inch guns. A recent report, submitted by Com. 

 Dahlgren, states, that when the ship has no inclination, the nine-inch guns 

 can be fired as fast as 32-pounders, but when the deck is inclined, the work- 

 ing of the guns is much retarded ; still, even at the inclination of eighteen 

 degrees, a well-drilled crew was able to discharge shells at intervals of sixty- 

 five seconds, and at an angle of five degrees in thirty-five seconds. When 

 the vessel was on an even keel, the large eleven- inch pivot gun could not be 

 fired so rapidly as the nine-inch cannon ; but it was worked more rapidly 

 when the deck of the vessel was inclined seven or eight degrees. At this 

 angle, seventeen shells were discharged in the same time as thirteen from 

 the nine-inch guns. As a pivot gun, it was found as manageable as a com- 

 mon sixty-four pounder ; and no difficulty was experienced in making such 

 heavy ordnance secure in the most stormy weather. 



It is not stated how far these guns carry. The target was placed only at 

 1,000 yards distance, but they can, undoubtedly, send shells much further. 

 The large eleven-inch gun weighs, with its carriage, no less than twelve and 

 a half tons. 



ON THE MANUFACTURE OF SHELLS (BOMBS). 



In 1854 the demand for the ordinary cast-iron shells in England having 

 been extremely urgent, many of the more eligible fotinderics of the kingdom 

 engaged in their manufacture ; still, from numerous difficulties which axe 



8* 



