The existence of a Central Heat not proved. 215 



Huttonian and every other geological sectary who relies on this 

 postulate, I say, be cautious : " iricedis per ignes dolososJ" 



The only observation I recollect to have met with in favour 

 of central heat is, that the deepest mines ai-e the warmest — be it 

 so ! Might not a geologist by jmrity of reasoning argue thus ? 

 In travelling from Rome to ClMuaonix, the country becomes 

 continually more and more mountainous ; some of the peaks of 

 Chamonix are from ten to fifteen thousand feet above the level 

 of the sea. Imagine, therefore, what they must be at Ham- 

 burgh ! ! 



If mines derive their temperature from heat lodged in the 

 centre of the earth, the temperature ought to vary with their 

 distance from the centre ; and, therefore, since the earth is an 

 oblate spheroid, the mines of Scandinavia ought at the same 

 depth from the surface to be proportionally warmer than those 

 of tropical countries ; a result which has never been, I believe, 

 even suspected. 



The existence of central heat, in the sense and to the extent 

 assumed in the Huttonian theory, is contrary to all our expe- 

 rience. If heat there be in the centre of the globe, it must have 

 the properties of heat and none other. I ask not how the heat 

 originally was lodged in that situation, for the origin of all 

 things is obscure ; but I ask why, in the countless succession of 

 ages which the Huttonian requires, the heat has not passed away 

 by conduction, and if it has passed away, by what other heat it 

 has been replaced ? 



Dr Chalmers, in speaking of Sir Isaac Newton, observes, tliat 

 it was a " distinguishing and characteristic feature of his great 

 mind, that it kept a tenacious hold of every position which had 

 proof to substantiate it ; but a more leading peculiarity was, 

 that it put a most determined exclusion on every position desti- 

 tute of such proof. The strength and soundness of Newton's 

 philosophy was evinced as much by his decision on those doc- 

 trines of science which he rejected, as by his demonstration of 

 those doctrines of science which he was the first to propose. 

 He expatiated in a lofty region, where he met with much to 

 solicit his fancy, and tempt him to devious speculation. He 

 might easily have found amusement in intellectual pictures ; he 

 might easily have palmed loose and confident plausibilities of 



