Colorado College Studies. 



C'ollectin,!:^ tlie ivsiilts just obtaint'il, we have 

 dp _''" 



X 

 Y- 



f'dr 



dp 



rrdo 



V'l\ 





„ dp _ '>»; 

 pdz <if 



The equation of continuity is 



d{ur) /^^' I ''^'"'_r| 

 dr do dz 



It is unnecessary to derive this last equation, since the 

 method by which it is obtained is identical with that used 

 to obtain the similar equation referred to rectangular co- 

 ordinates. 



Spherical Co-ordinates. — Angle WOF (in Fig. 9) = ^ and 



QOD=<f. Let u, V and w represent the velocities in the direc- 

 tions ?•, and <f respectively, v and w being angular; X, Y 

 and Z are the symbols for the corresponding impressed forces. 

 The mass of the element F3I is 



," (//• rdo r sin " dc = )n. 



