20 C. V. L. Charlier 



For the differentialcoefficieuts of A we get 



N' dA ( di , 8vj\ 



+ (ß.«3-ß3«.)(cg-.^|) 



where 



But we have 



so that 



N = a,^ -|- a^T] -|- = sin B cos yl. 



ßl ^-2 — ß2 «1 = — T3 



ß2 °'-3 — ß3 «2 = — T, = O 



p3 — «3 = — Y2 ■ 



di , 



+ T2(C 



and in Hke manner: 



cos ^A d'^ \ " 3w 



A direct computation gives 



and 



9C . 8ï] . , 



8C ^df] 4 . 



