Abstract
It is said that the parts surrounding gas-zones in a coal seam are more porous and broken than other parts; and there, the author thought that the sample of coal brohght from such parts might discharge the included gas rapidly when it was put in vacuum. The author made a testing apparatus of the rate of secretion of gas form the sample of coal and tested these rates of the samples-brought from the Horonai coal seam mid the Onoura coal seam (under some conditions).
The author found that op Δp (index of the rate of secondary secretion of gas) was almost linearly proportional to the porosi ty and had no relation to the friability of sample of coal, while q (index of the volume of primary secretion of gas) was linearly proportional a little to the later and had little relation to the former.
