(5]{) PROFESSOR KELLAND ON GENERAL DIFFERENTIATION. 



d-* 1 / s' \ , / X -' 



\2^ z + a Y,J z + a. I 



d-'' 1 l':? a«2 oirz\ 3z' as' 



\ 6»/ z + a Q<J z + a / 



1 ~' a~' 



---^ (i'+Sas^' + Sa-z + a'^ log(£ + o) + ^ + -^ 

 b 4 4 



= _ 1. (^ + 3a=' + 3a=^ + a=) log (--+ a) + i||^ 



Which results being substituted in the general formula for the attraction, give 

 attraction = -^ | - 8 a R (a + R) log (a + R) 



+ 8(a' + 3aR + R') (a + Rloga + R-2R) 



- 24 (a + R) (^^i^ log ^+R - 3 R' - a^^ R^ 



„. /o + R', — t> 22 _3 5 — P-P3 a-RlR) 

 + 24/—^ loga + R-— R'- g o-RR ^ | 



= J^|r(8a' + 16flR + 8R0 (a + R)-8 (a + R)' ~j x log (a + R) 



-16R(o' + 3aR + R-) + 24(o + R)(fl!R + 2R') 

 _^R"_24aR'-8a-R | 



= J!L-. |-16a=R-48aR'-16R' + 24a=R 



+ 48aR- + 24aR^ + 48R'-^R^-24«R'-8a=R I 



_47rR= 1 



