64 
emerging the streams will expand again, as shown in the 
figure, the pressure falling and the velocity increasing, 
until the pressure in the streams is equal ^2 when in all 
probability the motion will become unsteady. 
If is greater than ’527^1, the only possible form of 
motion requires the pressure in the necks to be ^2 at which 
point the streams become parallel until they are broken up 
by eddying into the surrounding fluid. 
6. There is another way of looking at the problem which is 
the first that presented itself to the author. 
Suppose a parallel stream flowing along a straight tube 
