On the Propagation of Sound in Water

(H. Barkhausen and H. Lichte. Quantitative Unterwasserschallversuche. Ann. d. Physik 62, p. 485—1920).

Using an electromagnetically excited source of sound vibrations, the authors studied the propagation of waves under water and showed that the limiting sound intensity corresponds to \(10^{-15}\) watt/sec.

The propagation of sound takes place with an attenuation not inversely proportional to the square of the distance, as in air, but according to a definite law of sound damping, which probably depends on the nonuniformities of temperature in the medium.

This explains why, generally speaking, in summer signals under water propagate over a shorter distance than in winter. The range of propagation of signals in the sea (Ostsee) was 10 kilometers in summer and 20 kilometers in winter; moreover, near the shores the propagation range decreased. With attenuation inversely proportional to the square of the distance, the propagation should have reached 1000 kilometers. Within the limits of tones audible to the ear, the damping does not depend on frequency.

P. Lazarev.