Effect of amplitude on velocity of a plane wave in a gas.—In a former paper (Phys. Rev. 28, 229, 1926) it was pointed out that the velocity of a transverse wave along a string is not independent of the amplitude and that for different frequencies to travel with the same velocity the ratio $\frac{a}{\lambda }$ must be constant, as for light waves (Zeits. f. Physik 8, 112, 1921). The same result is here proved for plane longitudinal waves in air.

• Received 12 January 1927

DOI:https://doi.org/10.1103/PhysRev.29.892