218 



Mr. Mallet on the Physical Conditions 



a combination of tensile strength and elastic range together, as shall give the highest 

 value to the coefficients Te and Tr- How little this may be expected from the 

 continent of Europe, in preference to the productions of Great Britain, may be 

 judged of by the following Table ix., compared with subsequent ones. The 

 measures are generally below those assigned by British authors. 



Table IX. 

 Ultimate Cohesion at Rupture, according to Continental Authors, in English Weights and Measures. 



Mr. G. Eennie's result for gun-metal is, doubtless, greatly below the truth, 

 yet his are almost the solitary experiments published up to this date on the 

 strength of this widely used material for cannon. In contrast with the iigures 

 of Ardant and Dufour, it forcibly shows the effect of molecular arrangement 

 on cohesion, and is given chiefly with that view. 



150. I shall conclude this branch of the subject with Table x., in which all 

 the conditions, as respects elasticity and extensibility, of the several materials for 

 ordnance are presented together, the data being from continental experiments : — 



* This agrees nearly with the American Government experiments. See " Report on Properties 

 of Metals for Cannon." By authority of Secretary at War. Philadelphia, 1856 ; and Note N. 



