Cox, R. N. and W. A. Clayden (1955). 



Air Entrainment at the Rear of a Steady Cavity. 



Proceedings of National Physical Laboratory Symposium on Cavitation in Hydro- 

 dynamics, H.M.S.O., 1956. 

 Garabedian, P. R. (1955). 



Calculation of Axially Symmetric Cavities and Jets. 



Stanford University, Applied Mathematics and Statistics Laboratory, Technical Re- 

 port No. 42, September 1955. 

 von Karman, Th. (1929). 



The Impact on Seaplane Floats during Landing. 

 N.A.C.A. Technical Note No. 321, 1929. 

 Monaghan, R. J. (1949). 



Theoretical Examination of the Effect of Deadrise in Seaplane-water Impacts, R.A.E. 

 Technical Note Aero 1989, 1949. 

 Pierson, J. D. (1950). 



Stevens Institute of Technology Report No. 381, July 1950. 

 Plesset, M. S. and P. A. Schaffer (1948). 



Cavity Drag in Two and Three Dimensions. 



J. of App. Phys., 19, pp. 934-939, Oct. 1948. 

 Rouse, H. and J. S. McNown (1948). 



Cavitation and pressure distribution: Headforms at Zero Angles of Yaw. 

 State University of Iowa, Studies in Engineering, Bulletin 32, 1948. 

 Schiffman, Max and D. C. Spencer (1951). 



The Force of Impact on a Cone Striking a Water Surface (Vertical Entry). 

 Comm. Pure and App. Math., Vol. IV, No. 4, pp. 379-417, Nov. 1951. 

 Schmieden, C. (1929). 



Die unstetige Stromung um einen Kreiszylinder. 

 Ing.-Arch I, p. 104, 1929. 

 Swanson, W. M. and J. P. O'Neil. 



The Stability of an Air Maintained Cavity behind a Stationary Object in Flowing Water. 

 Unpublished Cal. Tech. report, 1951. 

 Trilling, L. (1950). 



The Impact of a Body on a Water Surface at an Arbitrary Angle. 

 J. Appl. Phys., 21 (1950), 161-170. 



Vandrey, F. (1951). 



A Direct Iteration Method for the Calculation of the Velocity Distribution of Bodies 

 of Revolution and Symmetrical Profiles. 



Admiralty Research Laboratory Report, ARL/R1/G/HY/12/2, June 1951. 

 [Aeronautical Research Council Paper 14579 (FM.1665)] 



Wagner, H. (1933). 



Uber die Stoss-und Gleitvorgange an der Oberflache von Flussigkeiten. 

 Zeits. fur ang. Math, und Mech. 12, pp. 193-215, 1933. 



DISCUSSION 



G. Birkhoff 



My reactions to the preceding admirable review of recent contributions to 

 hydroballistics tend to be those of the cautious critic. 



A critical review of impact and water entry theory was initiated several years 

 ago by E. Cooper, H. Wayland, and myself. A careful study revealed wider dis- 

 crepancies between theory and recorded observations than might be inferred from the 



133 



