XX. On the absorption and radiation of heat of gaseous and liquid matter.—Fourth memoir

In his former researches on the absorption and radiation of heat by gaseous matter, the author compared different gases and vapours at a common thickness with each other. In the first part of the present communication he determines, in the case of several gases and vapours, the absorption effected by different thicknesses of the same gaseous body. His least thickness was 0·01 of an inch, and his greatest 49·4 inches; thus the thickness varied from 1 to nearly 5000.