On the temperature of the earth and sea, in reference to the theory of central heat : a lecture, delivered at the Royal Institution, February 20th, 1846, Lord de Mauley, V.P. in the chair / by Alfred S. Taylor.

  • Taylor, Alfred Swaine, 1806-1880.
Date:
1846
Catalogue details

Licence: Public Domain Mark

Credit: On the temperature of the earth and sea, in reference to the theory of central heat : a lecture, delivered at the Royal Institution, February 20th, 1846, Lord de Mauley, V.P. in the chair / by Alfred S. Taylor. 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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    descends must be small, and it will finally meet the ascending currents of caloric proceeding from the interior of the globe, whereby an equilibrium will be established. INTERNAL HEAT. We now, however, anive at the important fact, that if a ther- mometer be carried below this invariable stratum, it imme- diately begins to rise, and in a degree subject to some local exceptions, proportioned to the depth to which it is carried. It is obvious that this increase of temperature cannot be due to solar influence.—1. Because the existence of a zone of inva- riable temperature shows that the power of the sun must be hmited to that portion of the earth’s crust which is above it.— 2. Because, if the interior heat of the mass of the earth were due to external or solar influence alone, the thermometer should fall just in proportion as we descend below the invariable stratum. But the reverse of this is the fact, as we may pre- sently be able to establish from the results of accurate obser- vations. Hence we are irresistibly led to this conclusion—that in going below the invariable stratum, we are approaching some great source of heat, which must be situated within the interior of our globe. It is not to be supposed, however, that the same increase is obseiwed at equal depths in all places. As there are isothermal lines over the surface, so there are isogeothermal lines below it. Thus it was obsen’’ed that among five of the principal mines of Cornwall, in three the air had a temperature of 64° at 500 feet below the surface; but in two of them it was necessary to go to the depth of about 700 feet, in order to obtain this temperature. An isogeothermal line is, therefore, a curve of equal temperature below the invariable stratum, and when ■widely distant places are taken, considerable deviations ai’e found. Thus, in the latitude of Paris, it was ascertained, by sinking the well of Grenelle, that in order to obtain a tempera- ture of 72, it was necessary to go to the depth of thirteen hundred feet. In the Monkweaiinouth mine near Sunderland, the same temperature was obtained only at fifteen hundred