Chta-Shun Yth 
ae (34) 
@ being a velocity potential for u and w 
Let F bea function of x, y, z and t defined by 
e (35) 
(36) 
In view of (34) and the third equation in (29), differentia- 
tion of (36) gives 
(37) 
Assuming for all dependent variables the factor exp i(kz - ot), we 
can write (37) as 
(38) 
Eo °= ohy 
The subscripts in (37) and (38) indicate partial differentiation. Re- 
calling that the first and third equations in (29) are 
and combining (36) and (38) into 
1406 
