On underground temperatures : with observations on the conductivity of rocks, on the thermal effects of saturation and imbibition, and on a special source of heat in mountain ranges / by Joseph Prestwich.

  • Joseph Prestwich
Date:
1886
Catalogue details

Licence: Public Domain Mark

Credit: On underground temperatures : with observations on the conductivity of rocks, on the thermal effects of saturation and imbibition, and on a special source of heat in mountain ranges / by Joseph Prestwich. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    The subject of underground temperature is far from being new. It attracted attention a century and a-half ago, some observations liavinor been made by Gensanne in 1740 in the mines of Alsace, which if we take the mean annual temperature at the mines of 47° F,, give, curiously enough, an incj'ease of 50 feet per degree Fahr. Towards the end of the century, a few experiments were made by Saussure in Switzerland, and by Humboldt in America, but the more important ones were those made by Daubuisson in 1803, in the mines of Saxony and France, which gave a rate of increase varying from 54 to 72 feet per degree F. De Trebra carried on similar ob- servations in one of the Saxony mines for two years, which, taking the surface temperature at 44°, show an increase of 57 feet per 1° Fahr. Passing over some minor observations, we come to the series of careful and systematic observations commenced in Cornwall by Dr. Forbes and by Mr. R. Were Fox, about 1820, and which were carried on by the latter continuously until 1857. Other Cornish geologists followed, Mr. W. J. Henwood especially, who between 1837 and 1858, made a large number of experiments, not only in Cornwall, but also in the mines of South America. Notwithstanding that the instruments had not the perfection of those of later date, the observations are of great value, as they were conducted under very varied conditions, and with a full understanding of the various causes of interference to be guarded against. They show very con- siderable variations in the rate of increase with depth. Mr. Fox records a range for 1° F. of from 32 to 70 feet, from which De la Beche deduced a mean from 46 to 51 feet; and Henwood, while finding the results to range as widely as did Mr. Fox, nevertheless estimated from a large number of averages the gi-adient for 1° F. to be from 37 to 41 feet only. In 1822, Cordier published his celebrated “ Essai sur la Tempera- ture de ITnterieur de la Terre,” and in this he recorded the observa- tions previously made by Gensanne, Daubuisson and Fox, together with some observations made by himself in the coal-pits of France. The several results showed variations extending from 13 to 57 metres per 1° C., but he concluded the mean to be about 1° C. per 25 metres of depth. Amongst the most careful of the early observations are those made by De la Rive and Marcet in an artesian well at Pregny near Geneva. In this case, the thermometer was protected against pressure, and the result gave a rate of increase of 48^ feet per 1° F. This was shortly followed by Professor Phillip’s well-known observations in the deep coal-pit of Monkwearmouth, Sunderland ; great precautions were taken against error, and in the result an in- crease of 1° for every 62 feet of depth was obtained. h 2
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