INFL. OF DIFFUSION ON THE PRoPAG. or BouNDARY Waves. 11 
p 
Iq 
og = fox coth Ah — 7 "Er iA dz , 
0 
whence: | 
de | LEN g 
13) Oca Te d(x coth kh” + 4) . 
q- E da(k coth kh" + 35) , 
from which expressions the corresponding one for w is readily cal- 
culated. 
Before proceeding further, it may be well to verify that the om- 
missions made are really justified. "The delicate point is in the ocur- 
g NA N : 
rence of the factor 73, which in many cases may attain considerable 
numerical values. Consider for instance 
m, 
; 
7 för GE 
0 
which was neglected above, and introduce for g the value given by 
13): we must require that the ratio 
för dz fo az du 
14) Te UE: aa 
be small compared with unity. Suppose that r^ does not greatly dif- 
fer from the value given by 10), then sinee approximately: 
9 coth kh’ == 9" coth kh" — m är kh" a 
