I860.] to the Efficiency and Welfare of Military Forces. 247 



bronze field guns, afford an interesting illustration of the application 

 of the above system to the construction of very light and durable 

 cannon. This gun consists essentially of rings, partly welded together 

 so as to produce a cylinder or barrel of sufficient length, and partly 

 shrunk one upon another, so as to impart the requisite strength to the 

 structure. The rings themselves are from two to three feet in length, 

 and are formed out of long bars, which are coiled up, when at a red 

 heat, into spiral tubes, and afterwards welded into solid rings or tubes, 

 by a few blows from the steam-hammer, applied to one end of the 

 heated coil, while in a vertical position. The rings are united, to 

 form the barrel of the gun, by raising to a welding heat the closely 

 proximate extremities of two rings, placed end to end, and then ap- 

 plying a powerful pressure to the cold ends of the rings. In the large 

 guns, a second layer of rings is shrunk on to the first set, or barrel, 

 throughout the length ; but in the smaller guns, it is only behind the 

 trunnions that two additional rings are shrunk on, one over the other. 

 The outer ring is exactly like tliose already described ; but the inter- 

 mediate one is prepared by bending two iron slabs into a semi-cylindri- 

 cal form, and then welding them together at the edges. In this way, 

 a cylinder is obtained in which the fibre of the iron is arranged longi- 

 tudinally instead of transversely, as in the other rings. This arrange- 

 ment is adopted, because that part of the gun has to sustain the prin- 

 cipal force of the thrust upon the breech, on the discharge. It is into 

 this portion that the breech-screw (made of steel) fits, by means of 

 which a moveable plug of steel, provided with a soft copper washer, 

 is pressed up against the end of the barrel, when the gun has been 

 loaded. The breech-screw being hollow, the charge is introduced 

 through it into the gun, on the removal of the plug. 



This gun, built up of so many pieces accurately welded and turned 

 and fitted, with its 30 or 40 grooves, its neat lever-arrangement for 

 working the breech-screw, its admirable sights for giving direction, 

 and various other arrangements, contrived so as to render it a most 

 complete and perfect weapon, is undoubtedly very costly as compared 

 with the ordinary cast-iron gun. But, owing to the admirable system 

 of manufacture and the beautiful mechanical appliances brought to 

 bear upon the production of each part, the original cost of the gun has 

 already been very much diminished ; on comparing the price of a 

 12-pounder gun with that of a bronze gun of the same calibre, which 

 it has now superseded, the latter is found to be about double the 

 expense. The price of iron used for the manufacture of the Arm- 

 strong gun is £19 per ton ; it is the best description of malleable iron, 

 bearing a tensile strain of about 74,000 pounds on the square inch. 

 The present cost of a 12-pounder gun (weighing 8 cwt.) is about £93. 

 The value of gun-metal is about ^£125 per ton ; and the cost of a. 

 12-pounder gun of this material (weighing 19 cwt.) is £175. 10*. 

 Of the latter, it may be said, that when no longer serviceable it may be 

 re-cast, while an old Armstrong gun cannot be re-converted into a 

 new one. But, on the other hand, the average number of rounds 



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