Mr Davy's Observations on Springs, Sfc. in Cornwall. 75 



Art. XIII. — Observations on the Temperature of Springs, 

 Wells, and Mines in Cornwall. By John Davy, M. D. 

 F.R. S. Communicated by the Author. 



I he following very interesting observations, on the tempe- 

 rature of springs and mines in Cornwall, were made by Dr 

 Davy after his return from Ceylon. They formed an appen- 

 dix to the valuable Hydrographical Journal of his voyage, 

 which we have published in our preceding numbers. The la- 

 bour which is necessary in ascertaining temperatures under 

 such circumstances has deterred many persons from prosecut- 

 ing so important an inquiry ; and the difficulty of making 

 them correctly throws a doubt upon all those observations 

 which have not been made by observers of known accuracy 

 and experience. 



We therefore attach a high degree of value to the following 

 temperatures, because they were measured by the nicest in- 

 struments, and by a philosopher distinguished for his accu- 

 racy. 



We may safely conclude, for the reasons here given, that 

 the temperature of the earth in Cornwall is not far from 542° 

 of Fahrenheit, which is than that of the atmosphere.* 



Penzance. 

 August, 10, 1820. — Temperature of the well at Alverton 

 55°, 5, that of the air being 70°, at 11a. m. 



The Boy Mine. 

 August 30, — It is many years since this mine was wrought. 

 The engine-shaft is now full of water. Its temperature to- 

 day, at 6 P. M., was 55° at the surface. 



Huel Mine, just by Huel Virgin. 

 It is many years since this mine was worked. The tem- 

 perature of the water, in what appeared to be the adit-shaft, 

 was, at 7 p. m., 55°. The water was about 30 fathoms from 

 the surface, and it may be assumed to be running from the 

 mine. 



* See Dr Forbos's Observations on the Climate of Penzance, and the Dis- 

 tr i'l of the Land's End in Cornwall. Penzance, 1821. 



