X. On the Progress of Heat when communicated to Spheri- 
cal Bodies from their Centres. By Joun Prayratr, 
F.R.S. Lonp. Sect. R.S. Evin. and Professor of 
Natural Philosophy in the University of Edinburgh. 
[ Read March 6. 1809.]} 
N argument againft the hypothefis of central heat has 
been ftated by an ingenious BENS as carrying with 
it the evidence of demonftration. 
“cc 
“ Tue effential and charadteriftic property of the power 
producing hear, is its tendency to exift every where in a ftate 
of equilibrium, and it cannot hence be preferved without lofs 
or without diffufion, in an accumulated ftate. In the theory 
of Hutton, the exiftence of an intenfe local heat, acting for 
a long period of time, is affumed. But it is impoffible to pro- 
cure caloric in an infulated ftate. Waving every objection 
to its production, and fuppofing it to be generated to any ex- 
tent, it cannot be continued, but muft be propagated to the 
contiguous matter. If a heat, therefore, exifted in the cen- 
tral region ofthe earth, it muft be diffufed over the whole 
mafs; nor can any arrangement effectually counteraé this 
diffufion. It may take place flowly, but it muft always con- 
tinue progreflive, and muft be utterly fubverfive of that fy- 
{tem of indefinitely renewed operations which is repre- 
Wou: WLP, I: Yy “ fented 
