By combining the results of Kirchhoff and Knudsen, the effect of viscosity and heat conduction on a spherical sound pulse are found. A rectangular pulse becomes Gaussian, its peak moves with sound speed, its width increases proportionally to √t, and its amplitude decreases proportionally tox−1, wherexdenotes radial distance from the origin. This behavior is exactly the same as that of a pulse in one dimension, except for an extra factor of 1/xwhich accounts for the spherical spreading.