236 



ARTILLERY 



The drawing of this remarkable piece of artillery is presented although, except 

 experimentally, the mortar has never been used. It certainly is a remarkable example 



of engineering skill. Mallet's mortar is formed wholly of wrought-iron in concentric 

 rings, and each mortar is separable at pleasure with 13 pieces, the heaviest weighing 

 about 11 tons, the entire mass being 52 tons. 



The position attained by Rifled Ordnance manufactured on the principles advocated 

 by Sir William Armstrong is such, that it appears desirable to describe the mode of 

 constructing those guns. Sir William Armstrong himself describes the principles by 

 which he has been guided in the construction of his guns, in his paper communicated 

 to the ' British Association,' and reprinted in ' The Industrial Resources of the Tyno, 

 Wear, and Tees. ' With some slight alteration this has been retained as the best possible 

 source of information. 



'In the month of December, 1854, my friend Mr. Rondell, the well-known engineer, 

 submitted to Sir James Graham a communication he had received from me suggesting 

 the expediency of enlarging the ordinary rifle to the standard of a field-gun, and using 

 elongated projectiles of lead instead of balls of cast-iron. This communication was 

 handed by Sir James Graham to the Duke of Newcastle, then Minister of War, with 

 whom I had an interview on the subject in company with Mr. Rendell. 



' At this interview I was authorised by his Grace to carry my views into effect, by 

 constructing, upon the plan I had suggested, one or more guns, not exceeding six in 

 number, and to make the necessary experiments in connection with the subject. 



' In acting upon the authority thus received, I deemed it expedient to confine myself, 

 in the first instance, to the production of a single gun, but to make that one gun the 

 test, not only of the principles I had recommended, but also of the feasibility of load- 

 ing field-pieces at the breech, and applying certain mechanical arrangements to 

 counteract recoil, and facilitate the pointing of the gun. 



' The substitution of elongated solid projectiles for spherical bullets is an essential 

 step to the attainment of very extended range in artillery-practice ; but the lengthen- 

 ing of a solid projectile involves the necessity of strengthening the gun to enable it to 

 resist the greater intensity of force which becomes necessary to give the required 

 velocity ; and this object can only be effected, consistently with lightness, by construct- 

 ing the gun of steel or wrought-iron instead of cast-iron or bronze. The tensile strength 

 of these several materials is exhibited in the following Table : 



Breaking strain per 

 square inch of section. 

 Cast-steel, about . . . . . .60 tons. 



Sheer-steel . 42 , 



Wrought-iron . 



Bronze or gun-metal, about 



Cast-iron 



26 

 16 



' The first and strongest of these substances, nz. cast-steel, may be set out of the 

 question, as it appears impracticable, in the present state of manufacture, to produce 



