A new photographic technique is described, for observing velocity fields in water, induced by the entry of solid missiles. The results of a number of observations are given, and compared with theoretical formulas. The corrections involved in the method are analyzed theoretically, and the theory of the corrections confirmed experimentally. It appears that the method is well adapted to velocity fields 5–100 feet per second, created by objects several inches or more in diameter, but may lead to troublesome corrections at other speeds or with smaller objects.