Air From the Ground.

South Canterbury Times, Issue 7066, 11 February 1893, Page 2

Air From the Ground.

In some deep mines the air is sometimes good and sometimes “ foul. :> An inquiry into the circumstances of a variable mine of this sort in Victoria has been made by Mr A. M. Smith, director of the Ballarat School of Mines, He states that the outflow of foul air from the porous ground and abandoned workings was occasioned and regulated by the stale of the weather. The occurrence of foul air was always accompanied by a fall in the barometer. The diminution of atmospheric pressure which the falling barometer recorded extended, to the workings below, and allowed the gases imprisoned within the porous strata and the old workings to escape Whenever , the barometer fell, no matter what direction the wind might be, the mines responded, and an outflow of gas resulted, the amount depending upon the extent of the fall. Indeed, the mines might be regarded in this respect as huge and most sensitive barometers. When the barometer rcee again the reverse action ensued, the air in the open mines being pressed back into porous ground, and the good air followed up and entered after it until equilibrium was restored. As the northerly winds were usually accompanied by a low barometers the misers attributed the outbursts of foul air to them —The facta here pointed out, that when the barometer rises air is driven into the ground in mines, and when the barometer falls the air is released again, and other gases with it, are of more general occurrence than merely in deep mines. In the mines the facts are more patent, because the quality of air in mines is more closely observed, and because when deleterious gases are emitted, they are retained in the workings as in a vessel. The compression of air into tho ground by a rising barometer, however, and its escape under a falling barometer, must take place ell over the earth’s surface. This is a consideration which gives a new meaning to foul subsoils, say of dirty backyards. The variations of the barometer alternately cause large quantities of air to be driven into and then brought out of the ground, and if the ground is foul with gas producing substances, the gases will exude with the air, and according to their nature may be highly injurious to health. This eternal <: breathing ”of the earth generally would surely te worth careful study, elsewhere than in mines.