Abstract
If the partial potential temperatures and water vapor contents for an aerological sounding are plotted against each other on the equivalent potential temperature diagram, one obtains the characteristic curve for this air column. Some important properties of these curves have been derived by Prof. C. G. Rossby(1). The representation of upper air temperatures by the metheod of the emagram is, from the thermodynamical aspect, the best that has yet been proposed. The characteristic curve. which ordinarily accompanies it, is a practical means of representing the conservative properties of the individual air masses. The characteristic curve proves to be of great importance thermodynamically and may serve for the estigram(2)
