39 
905 
line, Hence, along a stream-line, 
(13,5) pee a - pe + constant 
In order to find the preesure one may determine Y from Cis) 
and the given boundary conditions, and substitute in (13,5). 
The eolution of (13,3) is the same in the linear end the non- 
linear approximations, and 16 given by Kirchhoff's equation in 
which c is made infinite. It then follows from (13,5) that the 
"“scoustic pressure" may be corrected by aubtracting pe from 
it. 
