44 EXPERIMENTS on WHINS TONE and LAV J. 



the fupcrincumbcnt mafs, many important phenomena of the 

 mineral kingdom, which he has thus reconciled to his fy- 

 ilem. 



One nccefTary confequence of the pofition of thefe bodies, 

 feems, however, to have been overlooked by Dr Hutton him- 

 fclf : I mean, tliat, after their fufion, they mud have cooled 

 very flowly ; and it appeared to me probable, on that account, 

 that, during their congelation, a cryflalli/.ation had taken place, 

 with more or kfs regularity, producing the ftony and cry- 

 ftallized ftrudture, common to all unftratified fubflances, 

 from the large grained granite, to the fine grained and 

 almoft homogeneous bafalt. This conjedure derived addi- 

 tional probability from an accident fimilar to thofe former- 

 ly obferved by Mr Keir, which had juft happened at Leith : 

 a large glafs-houfe pot, filled with green bottle glafs in fu- 

 fion, having cooled flowly, its contents had loft every cha- 

 racfler of glafs, and had completely aflumed the ftbny ftruc- 

 ture. 



These views made part of a paper which I had the ho- 

 nour of laying before this Society in 1 790 * ; and about the 

 fame time I determined to fubmit my opinions to the tell: 

 of experiment. I communicated this intention to all my 

 friends, .and in particular to Dr Hotton ; from him, how- 

 ever, I received but little encouragement. He was imprefTed 

 with the Tdea, that the heat to which the mineral kingdom 

 has been expofed was of fuch intenfity, as to lie far beyond 

 the reach of our imitation, and that the operations of nature 

 were performed on fo great a fcale, compared to that of 

 our experiments, that no inference could properly be drawn 



from 



* Particdlar reafons induced me not to piiblifh this paper at full length; but, 

 •wifliing to preferve a record of feme opinions peculiar to myfelf which it containr 

 cd, I introduced a Ihort abftraft'of it into the Hiftory of the Tranfaflions. 



