involved in the Construction of Artillery. 



213 



Table VI. 



'Relation of Elastic Limit, and of Extension, to ultimate Cohesion, according to Continental Experi- 

 menters, in English Measures. 



138. From these Tables the succeeding diagram has been produced, in 

 which the quadratures of the four curves indicate the values of T^ and 7"^ for 

 cast-steel, harsh strong 

 iron, soft strong iron, and «" 

 wrought-iron of extreme ^^ 

 ductility, but of moderate ^ 

 strength. 



From rf, the origin, dy 

 is the ordinate of strain, 

 in kilogrammes, and dz 

 the abscissa of extension, 

 in millimetres. The curve 

 d'yl, nearly a right line, 

 is that for the extension 

 of cast-steel ; the curve 



d'B that for harsh stronsr "^ "^ 'io~3o~M~~m~~co~iiJ~lo 90 mo m mo no no a 

 wrought-iron ; d'C the curve for soft strong iron ; and d'D that for extremely 

 ductile, but not very strong iron. - 



139. On the known principles oi vis viva, the " work done" in each case 

 in producing these extensions will be equal to one-half the quadrature of each 



VOL. XXIII. 2 F 



