1270 
function of the velocity. 
2z 
Pp -w[h a at ria (16.3 
As already remarked in par. 5, the pressure pulse computed 
from (16.3) and (16.1) is very nearly linear for shocks, 
whose pAr &1.6. From this it follows that the kind of 
pulse considered here, type (c), is essentially equivalent 
to a pulse of type (a). 
i7. It is convenient to choose units of length and 
time so that a = 1 and so that the initial length of the 
incident pulse is also wnity. Then the boundary conditions 
(16.1) and (16.2) become 
u, (x,0) = = B+ Bx, x¢l (17.1 
u, (x,0) = 0 P Xa 
loos 
Eo ei0)= Yu (17.2 
18. One could specify the initial pressure-distribution 
instead of the initial velocity-distribution, as has been 
done here. In fact, this would be desirable, since gauges 
are usually interpreted to give pressures rather than 
velocities. The reason for adopting the opposite procedure 
here is that it is analytically more convenient to regard 
the velocity as given. Since, however, the experimental 
data generally concern pressure, it is necessary to have 
ae se 
