

[) 





in 





n foli, 



e 



andi 



J fliiii 

 itim 



holl 



filtrs 



fluil 



ons( 

 ithef 



i toi 



Hill 



f tl 



[1 



tl 







c 



oi' 



r 



i 



HUTTONIAN THEORY. 



21 



pare the operation of that eleraePxt vvhen it con- 

 folidated the (trata, with the refuhs of our daily 



experience 



The materials of the ftrata were 



difpofed, as we have already feen, loofe and 

 unconnected, at the bottom of the fea ; that 

 is, even on the moil moderate cflimatinn, at the 

 depth of feveral miles under its furRice. At 

 this depth, and under the preflure of a column 

 of water of fo great a height, the adion of heat 

 would differ much from that which w^e obfer\e 

 here upon the furface ; and, though our expe- 

 rience does not enable us to compute with ac- 

 curacy the amount of this difference, it never- 

 thelefs points out the dire6lion in which it muft 

 lie, and even marks certain limits to which it 

 would probably extend. 



' 4 



The tendency of an increafed preffure on 

 the bodies to which heat is applied, is to re- 

 ftrain the volatility of thofe parts which o- 

 therwife would make their efcape, and to 

 force them to endure a more intenfe adion of 



heat. 



A 



a certain depth under the furfa 



of the fe 



th 



p w 



fe heat migl 



r even 

 fore be 



f 



a 



y in- 



able to d 



ff the oily or bituminous parts from the infl 



ble matter the 



was 



heat 



found ftill 



parts, forming a fubft 



depofited, fo that, u^hen th 



thdrawn, thefe principles might b 



ted to th 



thy 



d 



b 



B3 



very unlike the re- 



fiduum 



^ 



