EEMAEKS OX THE TEMPEMTUKE OF THE 

 EARTH AS EXHIBITED IN MINES. 



AVITH SPECIAL REFERENCE TO OBSERVATIONS IN SOME OF THE 

 DEEPEST MINES ON THE GYMPIE GOLD FIELD. 



By WILLIAM FRYAR, Inspector of Mines, Queensland. 



[Read he/ore the lloi/dl Societi/ uf QueeiisJand, March 21st, 1889] 



The present and prospective importance of the mining industry 

 of the colony is my excuse for troubhng you with remarks wliich 

 have an important bearing on its prosperity and permanency, and 

 although the absolutely new data which can now be presented 

 is only very meagre, the facts and deductions therefrom may be 

 stated in order that attention may be drawn to the subject. 



The question of subterranean temperature has been touched 

 on by a few scientific gentlemen, but has scarcely had that 

 attention at the hands of persons actually and daily engaged in 

 underground opei'ations which it deserves. It has, however, 

 been attempted to be shewn on various occasions that the 

 natural heat of the earth increases as descent is made into the 

 strata or rocks constituting its crust ; and that this increment 

 of temperature is at the rate of 1 deg. Fahrenheit to from 40 to 

 60 feet of descent, and that therefore the limit at which men can 

 work is quite within measurable distance, as indeed it would be 

 in our tropical mining fields if this theory held good, for with a 

 mean annual temperature of 67 degs. at Brisbane, and probably 

 10 degs. more on our Northern gold fields, a very short depth 

 below that to which we have now attained would reach 

 an atmosphere intolerable to be borne by human beings as at 

 present constituted. 



