471 



Yet both Dr. Hufton and he fiiew a ftrong inclination to adjuft 

 tnatters with their readers by pojlulate and adniiffion, rather than by 

 the more crabbed procefs of demonftration. 



Mr. Playfair fays, (feftion 163,) " a further poftulatum is introduc- 

 " ed in Dr. Hutton's theory, namely, that compound bodies, fuch as 

 " carbonat of lime, when the compreffion prevents their feparation, 

 " may admit of fufion." And (fe<flion 17,) " thefe efFecls of prelTure 

 " to refift the decompofition of bodies and to augment their fufibi- 

 " lity, once fuppofed, we {hall find little difficulty in conceiving the 

 " confolidation of bodies by heat." 



Mr. Playfair, convinced of the accommodating difpofitions of his 

 readers, now takes for granted that his fuppofition is admitted, and 

 fhews, that he fully underftands the importance of the conceffion, he 

 fays, (feftion 25.) " The principle juft mentioned, relieves us therefore 

 " from a difSculty that would have embarraffed, but could not have 

 " overturned this theory." 



Such is the fum of the demonflraiions, or poflulates, or poffibilities (for 

 it appears, much turns upon the word may) by which Mr. Playfair 

 endeavours to eftablifli the wonderful powers of his mailer's fubaqueous 

 foundery, it is for the reader to determine, with what fuccefs he has 

 laboured : I rauft now follow Dr. Hi'.tton through other operations per- 

 formed by the fame agent, fubterranean heat, not lefs wonderful^ though 

 totally diaerent. 



The third propofition concluding his theory, ii Hated by Dr. Hutton 

 himfelf, page 263. 



" That the ftrata formed at the bottom of the fea, had been ele- 

 " vated as well as confolidated, by means of fubterraneous heat. 



This elevation of the ftrata of the world from the bottom of the 

 ocean to the tops of our highefl; mountains, is one of the operations 

 which Mr. Playfair has told us, " alarms the imagination, and to which 

 " the mind cannot foon be familiarized." Yet, as if our imaginations 

 were not fufEciently alarmed already, and as if Dr. Button had not exerted 



the 



i 



