284 Trails. Acad. Sci. oj St. Louis. 



Equation (32) may be transformed into one involving a 

 third variable. Thus, the condition that 



P = 



is 



dhj 2 dy 5 i„ 51og.B 5 , ^^ ^ „„^ 



4 Airk 



provided n — j-^ and A — p2'T'2 ' 



This equation like (32) is not very encouraging in appear- 

 ance, and it may be that no closed solution can be made of 

 it, or that the solution will be too complex for further appli- 

 cation. 



Correction, p. 66^ line 21 from bottom, for ten read 

 twenty. 



Issued June 14, 1899. 



