A WARM SPOT.

Manawatu Herald, Volume III, Issue 92, 19 July 1881, Page 4

A WARM SPOT.

The extraordinar} degree of heat fojind in the depths of the great Comstock mine, Nevada, has drawn a good denl of attention to the causes of internal heat in mines and springs. The particular cai-ie is one which it is not possible to explain on any general theory of increase of temperature in proportion to depth, as it is obviously local, and therefore due to local conditions. The explanation offered is, that the heat is produced j by the decomposition of the deposits i of iron pyrites found in the mine. ! A writer in the Virginia Enterprise, published in the capital of Nevada, affirms that over the whole nrea of country which is underlain by the iron pyrites deposits a process of slow combustion is in operation, and can be traced by the appearance of the hot springs which make their way to the surface. He also asserts that there are indications that in parts of the country the combustion has burned out. As it spreads, according to this writer, its advance is shown by the breaking out of new springs of hot water and steam, and the burning out is proved by the cessation of this activity, and the disappearance of the springs. The following on this subject is worth quoting :— " At Steamboat Springs we probably see a big mineral vein (like the Comstock) in process of formation. Ages ago there was probably a line of hot springs along the course of the Comstocls. The mines of Europe and America, which are com-paratively'Qtilft-'tftr&reat depths, are undoubtedly ages and ages older than the Comstock. The Comstock is probably the youngest mine in any part of the world that is now known or being worked; Here, down in our lower levels, we are following close upon the heels of nature—^getting well down into her workshop. As to the heat-generating power of sulphur and iron, those who desire to do so may satisfy themselves. Take a few pounds of iron filings, borings, and drillings from a machine shop*, wet them, and mix in a pound or two of sulphur, then tamp the mixture firmly into a hole in the ground — like a post hole—covering it with two or three inches of dirt, and in a short time there wiltbe seen a miniature volcano, the batch of iron and sulphur taking fire spontaneously."