Proceedings of the British Association. 89 



' On the Temperature of the Earth in the Deep Mines of Lancashire 

 and Cheshire,' by Mr. Eaton Hodgkinson. These experiments were made 

 with thermometers belonging to the Association, and in the prosecution 

 of them the author has been very greatly assisted by the proprietors of 

 pits and others connected with them, who have kindly undertaken to ob- 

 serve the results themselves — thus saving the author the trouble, in 

 some cases, of going more than once into the mine. The object of the 

 experiments was to forward the views of the Association — which were, 

 to obtain, from observations made in various places, and at different 

 depths, some additional knowledge of the internal temperature of the 

 earth. In the salt mines of Messrs. Worthington and Firth, at Northwich, 

 in Cheshire, latitude about 53° 15', a thermometer placed in a bore hole, 

 3 feet deep in the rock, 112 yards below the surface, indicated a tempe- 

 rature of 51° to 514° Fah., and varied little or nothing between summer 

 and winter. In the deep coal mines of Messrs. Leeses, Jones, & Booth, 

 near Oldham, a thermometer, placed in a bore hole as before, 329| yards 

 below the surface, varied from 57° to 581° Fah., from observations made 

 for a whole year, by Mr. J. Swain. In the Haydock colliery, 201 yards 

 deep, about eighteen miles west of Manchester, and differing from it but 

 little in latitude, the temperature varied considerably, both in the same 

 hole and in different ones, but approached to 58°. The cause of these 

 anomalies the author has not discovered. The experiments were made 

 for him by Mr. William Fort. Other experiments are in progress. The 

 latitude of Manchester is 53° 30', and the mean temperature of the air 

 there is 48° Fah., from Dr. Dalton's experiments. 



Prof. Stevelly asked Mr. Hodgkinson, whether it was possible that 

 water could have access to those parts in which his thermometers had 

 been placed, particularly those placed in the stratum next under the 

 coal, at the floor of the mine ? — Mr. Hodgkinson thought not. — Prof. 

 Stevelly said, that the reason why he inquired was, that there were 

 certain kinds of coal, which when exposed to the action of water deve- 

 loped much heat. This was the case with all coals which contain 

 pyrites. The substance of which the floor of the mine was composed, 

 though nearly as hard as a metal, had such an affinity for moisture that 

 even the hygrometric moisture of the air would decompose it, and of 

 course develope more or less heat. — Prof. Forbes said it had been 

 clearly established that coal mines were improper localities for making 

 observations on subterranean temperature. 



The President said, that as the Report which was next on the list 

 was nearly allied in subject to the one at present under consideration, 

 it would perhaps be convenient to permit it to be read, and to discuss 

 both at the same time. 



' Report on Observations on the Temperature of the Earth at differ- 

 ent depths, made near Edinburgh, by Prof. Forbes. — These observa- 

 tions were commenced in Feb. 1837, and have been regularly continued 

 since. They were instituted at the expense of the British Association ; 



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