ei ea 
REPORT ON SUBTERRANEAN TEMPERATURE. 319 
these circumstances, as well as by the strata and the spheroidal 
form of the earth, on these phenomena. 
requested by the British Association? and I conceive that, in Siberia, Sweden, 
and other countries, there might be found willing coadjutors in the prosecution 
of such an investigation so interesting to science. In this Report I have con- 
fined myself to my own observations, or those which have been made for me; 
but I find, on looking over several series of results published by other indi- 
viduals, that they tend, more or less, to confirm the conclusions at which I 
have arrived ;—that the subterranean temperature does notincrease so rapidly 
in descending, at great depths, as at smaller ones; and it is remarkable, that 
the observations made long ago, in some mines of Germany, etc., indicate a 
temperature I think 50 per cent. less in the aggregate than the average of 
rid results obtained in the Cornish mines, as far as I am acquainted with 
them. 
