At page 5 of their recent communication on the composition of soil gases Messrs Russell and Appleyard give some data regarding gas which was extracted from portions of soil which had been placed in flasks, the air pumped out and the soil then allowed to stand for one or more days. The authors state that “the total amount of gas given up is not great.” As a matter of fact a little consideration shows that the volume of this gas was indeed comparatively very large.