XVIII. On the General Equations of the Motion of 

 Fluids, both Incompressible and Compressible ; and 

 on the Pressure of Fluids in Motion. 



By J. CHALLIS, MA. 



FELLOW OF TRINITY COLLEGE, AND OP THE CAMBRIDGE PHILOSOPHICAL SOCIETY. 



[Read Feb. 22, 1830.] 



I. Incompressible Fluids. 



1. The general equations relating to the motion of incom- 

 pressible fluids, are, 



(Poisson, Traitd de Mecanique, Tom. II. p. 486.) 



p is the pressure at any point, the co-ordinates of which are 

 X, y, z ; M, Vy to, are the velocities in the directions of x, y, z, 

 respectively; dF is put for XdxJrYdy + Zdz, in which X, Y, Z, 

 are the components in the directions of x, y, z, respectively, of 



Vol. III. Part III. 3 D 



