XIV. On the DiJ^sion of Heat at the Surface of the Earilu 

 By John Murray, M. D. F. R. S. Edin. 



(Head 2d May 1814 J 



AN argument which I had stated against the Huttonian 

 Theory of the Earth, in so far as it relates to the opera- 

 tion of a central heat, was honoured some time ago with a re- 

 ply by a distinguished Member of the Society. Respect for 

 the opinion of Mr Playfair led me to consider attentively the 

 reasoning he employed ; and still feeling some confidence in the 

 grounds on which the original argument rests, I propose to of- 

 fer a few observations with regard to it. The question farther 

 involves the consideration of the mode in which heat is distri- 

 buted at the surface of the globe. This, when minutely inves- 

 tigated, presents a very perfect arrangement, by which the 

 escape of caloric is prevented, while its equal distribution is 

 more effectually attained ; and the subject, under this point of 

 view, may have some interest, independent of its relation to any 

 controversial discussion. 



The argument which I had advanced is, That if a heat exist 

 in the interior part of the earth, operating for an indefinite pe- 

 riod, as is assumed in the Huttonian Theory, it cannot for such 

 a period remain, locally accumulated. It must diffuse iiself 



through 



