Penny Blood: Serial Sensation and Working-Class Entertainment — page 19: what you’re looking at

Machine-transcribed from the original scan — historical spelling and the odd misread are preserved.

oe 2 ON UNDERGROUND TEMPERATURE. {cu.1. indeed it is this circumstance, more than any other, which fixes a practical limit to the depth at which mining operations are possible, It is not the raising the minerals from profound depths, for the resources of modern engineering are quite competent to overcome any difficulty on that score; it is pot keeping the mines clear of water, for they are less troubled with its influx at great than at moderate depths; but it 1s the impossibility of furnishing the men with an atmosphere to breathe in below the temperature of the blood. For when the air has to be conveyed to long distances it acquires the tem- perature of the rocks, and no means have been yet suggested which could furnish it at the atmospheric temperature un- affected—or but slightly so—by its long journey through the subterranean passages. This increase of temperature, though universal, is not every- where the same. The average is about 1 degree Fahr. for between 50 and 60 feet of descent.’ Such is the result of very numerous observations. Some of these have been made by drilling holes in the rock in deep mines; others by lowering thermometers in Artesian bore-holes. A Committee was ap- pointed by the British Association to report upon the subject, and their reports extend from the year 1869. Much informa- tion upon the matter may also be gathered from the Reports of the Parliamentary Commission upon the Coal Supply. Unquestioned as is the fact, nevertheless the cause of this increase of heat has formed the ground for much speculation. The most obvious explanation of it is offered by the phenomena of hot springs and volcanos. These show us that, im some places at any rate, much higher temperatures exist at great depths than have ever been reached by artificial perforations. But these phenomena might be said to be local, while the general slow increase of temperature we have been describing exists more or less at every place. Are these phenomena directly connected? Are they indirectly connected? Or, are they altogether unconnected? Various answers have been re- turned to these questions. Among “practical men” engaged in mining operations an opinion seems to have prevailed that the increase of temperature COLA @ | NOOKS. COM: