1572 
the agreement between theory and experiment is quite good, in view 
of the scatter of the data, but at higher ranges there is considerable 
attenuation still to be accounted for. If the cavitation pressure 
had been chosen as an actual tension of some magnitude rather than 
zero, the theoretical curve would be moved upward resulting in even 
poorer agreement with the observations-e This gives some support to 
the assignment of a low breaking pressure for initiation of cavitation. 
16-4 Any complete quantitative theory of bulk cavitation mst take 
explicit account of the conditions and process of its initiation. 
The theory must go on to describe the way in which the bubbles abstract 
and scatter energy through the pressure field. It has been the view 
that sea-water possesses a unique breaking tension and that this 
essentially static pressure condition is the criterion for the initiation 
of bulk cavitation and the formation of spray domes due to transient 
pressure wavese Observations of cavitation” have led to the assign- 
ment of breaking tensions smaller by at least an order of magnitude 
(0-100 psi) than those deduced from photographs of the spray dome** 
(400-6000 psi). 
Breaking tensions obtained by spray dome measurements vary 
over an order of magnitude depending upon the smoothness of the sea- 
surface, the surface tension of the water, the dynamic structure of 
the Pressure wave incident at the surface, and even upon the particular 
aspect of the phenomenon from which the breaking tension is deduced. 
We are dealing here with the disintegration of a liquid surface into 
droplets, the onset of which is intimately connected with the condition 
of the surface. 
~ 96 ~ 
