On the Propagation of Sound in Water

(H. Barkhausen and H. Lichte. Quantitative Underwater Sound Experiments.
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 with a definite law of sound damping, which probably depends on temperature irregularities in the medium.

This explains why, generally speaking, in summer underwater signals 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 coasts the range of propagation decreased. With attenuation inversely proportional to the square of the distance, the propagation should have reached 1000 kilometers. The damping does not depend, within the range of tones audible to the ear, on frequency.

P. Lazarev.