114 Mr. L. Schwendler on the General Theory 



tial of c 1 with respect to x, i, and L; 



, , dc' , dd ,. , dd rr 

 dx di dh 



or 



6V= j- Sx + -jr 8i + -rr SL approximately ; 



which expression is perfectly true, however, for small variations 

 8x, $i, and SL. 



Now* ^ = N' +8c , = 



o' n' ' 



dd jx dc' 5,. dc 1 ~ T 



-,- 007 + -yr hi + -rrbb 

 a dx di dh 



■'•° pf+J+M 



dd dd 

 But as Sx, 8i, and dh are very small, and as neither -y-> ~p, 



m' 





b' 





N' 



K' 



m 



> 



N' 

 m' 



K' 



6' 



A' 



V ' 





K' 



_N' 



+£• 



fc' # 



tf 



m! 



6' 



m' ' 



but 



o m m 



Now 



K' 



Substituting for — its value, we get 



6' 





but 



N'=cV+a', 



but 



? =p 



or 



N' 



