MECHANICAL AND USEFUL ARTS. 55 



jectile to be fired gives better results, and is capable of a more extended applica- 

 , tion, than the construction which requires the compound projectile and soft 

 metal coating. Iu other words, the system of rifling by mechanical fit is capable 

 of doing much more than that of rifling by the force of the explosion. The latter 

 is a construction of which I cannot be said to have approved, otherwise I should 

 have adopted it. Among other objections to the use of the compound coated 

 projectile, one of great importance is, that it involves an arrangement which is 

 complicated, whereas the shaped hard metal projectile is far more simple, and 

 may be produced at less cost. Simplicity of arrangement and construction is 

 the special object I sought to obtain, knowing that in this, as in all other im- 

 provements based on mechanical principles, that system is the most perfect which 

 is reduced to its simplest elements. When this is done successfully it may gene- 

 rally be considered that the result cannot be surpassed. 



NEW GUN-METAL. 



In a discussion on Artillery at the Institution of Civil Engineers, 

 several facts of interest have been stated incidentally. Mr. F. A. 

 Abel, chemist to the "War Department, for example, replied to 

 an inquiry, — that he had been induced to make some experiments 

 upon the combinations of phosphorus with copper, and had found 

 that by the introduction of a small proportion of that substance, say 

 from 2 to 4 per cent, of phosphorus into copper, a Gun-metal was pro- 

 duced remarkable for its density and tenacity, and superior in every 

 respect to ordinary gun-metal (the alloy of copper and tin known by 

 that name). He believed the average strain borne by gun-metal 

 might be represented by 31,000 lbs. upon the square inch, whilst 

 the material obtained by adding phosphorus to copper bore a strain of 

 from 48,000 lbs. to 50,000 lbs. But the increased tenacity was not 

 the only beneficial result obtained by this treatment of copper. The 

 material was uniform throughout, which was scarcely ever the case 

 with gun- metal. The experiments alluded to were merely preli- 

 minary, and had been, to a certain extent, checked by the improve- 

 ments since introduced in the construction of field-guns, which had 

 led to a discontinuance of the employment of gun-metal. Sir Charles 

 Fox also thought the best guns would be made of iron mixed with 

 some other metals, such as wolfram and titanium, so as to ensure the 

 greatest strength and density. Mr. Musket had, he said, obtained 

 great density by mixing with iron a small per-centage of wolfram, 

 and great strength by the use of titanium. 



THE LANCASTER GUN. 



Mr. Lancaster has explained to the Institution of Civil En- 

 gineers, the causes of the temporary failures which had attended the 

 use of his oval-bored cannon. It was true, he said, that three were 

 burst at the muzzle in the Crimea, but it must be understood that 

 those which failed were the service-guns, bored oval on his system, 

 and not the guns specially made for the purpose. It was generally 

 supposed that the action of the shell in passing out of the bore burst 

 the gun. The fact was simply that the shells were originally made 

 in two pieces, the base of the shell being welded to the upper por- 

 tion. In practice this weld was often imperfect. Hence, at the 

 moment of the explosion of the service charge, the flame penetrated 

 through the defective weld to the charge within the shell. The 



