1860.3 to the Efficiency and Welfare of Military Forces. 245 



Alloys of copper and aluminium have been proposed ; but, apart from 

 the present great cost of aluminium, the readiness with which this 

 metal is attacked by alkaline substances, and the powerful corrosive 

 action which portions of the products of decomposition of po\^der con- 

 sequently exert upon it, preclude its application to the production of 

 a substitute for gun-metal. The effect of silicon in hardening and 

 greatly increasing the tenacity of copper has also received attention ; 

 and there appears little doubt that, the difficulty of producing on a 

 large scale an uniform compound of copper and silicon once overcome, 

 such a material would prove a most valuable substitute for bronze. 

 The effects of a small quantity of phosphorus upon copper are similar 

 to those of silicon ; the metal is greatly hardened, its uniformity may 

 be ensured, and its tenacity is also much increased. Copper containing 

 from two to four per cent, of phosphorus will resist a strain of from 

 48,000 to 50,000 pounds on the square inch, while the average strain 

 borne by gun-metal is about 35,000 pounds. Uniform compounds of 

 phosphorus and copper can, moreover, be prepared without difficulty 

 upon a large scale. By immersing pieces of phosphorus for a short 

 time in a solution of sulphate of copper they become coated with a 

 film of the metal, so that they may be safely handled, and thrust 

 beneath the surftice of liquid copper before the coating melts ; thus, 

 the phosphorus is readily combined with the copper without loss. 



The great success Avhich has recently attended the construction of 

 malleable iron guns, appears, however, to render it doubtful whether any 

 of the compounds above referred to, or others of a similar character, 

 will ever receive employment as materials for cannon. Attempts have 

 been made from time to time, for many years past, to produce forgings 

 of malleable iron of sufficient size for conversion into cannon. The 

 great difficulty of ensuring anything approaching uniformity of 

 chemical composition and physical properties in cast iron, and the 

 consequent great variation and uncertainty of the enduring power of 

 guns made of that material, acted as powerful incentives for the prose- 

 cution of such experiments. Experience gained during the recent war 

 was also unfavourable, partly to the employment of cast iron as the 

 material for the heaviest pieces of ordnance, and partly to the system 

 of casting these hitherto in use. An important series of experiments 

 recently carried on under the United States' Government, with refer- 

 ence to the application of cast iron for the production of cannon, had 

 furnished many valuable results ; and the continuation of these experi- 

 ments and enquiries, both in America and in this country, appeared to 

 promise considerable improvements in the general quality and uni- 

 formity of cast-iron cannon. Meanwhile, however, the importance of 

 securing, without loss of time, more uniformly durable guns, to which 

 the principle of rifling could be applied with greater security than to 

 cast iron, became an additional inducement for the renewal of experi- 

 ments with the view of producing wrought iron cannon of large 

 calibre. 



The attempts made by Nasmyth and others to produce large 

 Vol. III. (No. 32.) s 



