THEORY of the EARTH. 235 



in its natural fhape and fituation ; but if it had been by aque- 

 ous folution that the wood had been penetrated and confolida- 

 ted, all the parts of that body would be found in the fame na- 

 tural fhape and fituation. 



THIS, however, is far from being the cafe ; for while, in 

 fome parts, the vafcular ftruclure is preferved entire, it is alfo 

 evident, that, in general, the woody ftruclure is varioufly bro- 

 ken and diflblved by the fufion and cryftallization of the flint. 

 There are fo many and fuch various convincing examples of 

 this, that, to attempt to defcribe them, would be to exceed the 

 bounds prefcribed for this diflertation j but fuch fpecimens are 

 in my pofTeffion, ready for the infpe&ion of any perfon who 

 may defire to ftudy the fubject. 



WE may now proceed to confider fulphureous fub fiances, 

 with regard to their folubility in water, and to the part which 

 thefe bodies have acted in confolidating the flrata of the globe. 



THE fulphureous fubftances here meant to be confidered, are 

 fubftances not foluble in water, fo far as we know, but fufible 

 by heat, and inflammable by means of heat and vital air. 

 Thefe fubftances are of two kinds j the one more fimple, the 

 other more compound. 



THE moft fimple kind is compofed of two different fubftan- 

 ces, viz. phlogifton, with acid or metallic fxibftances ; from 

 which refult, on the one hand, fulphur, and, on the other, me- 

 tals, both properly fo called. The more compound fort, again, 

 is oily matter, produced by vegetables, and forming bituminous 

 bodies. 



THE firft of thefe is found naturally combined with almoft 

 all metallic fubftances, which are then faid to be mineralized 

 with fulphur. Now, it is well known, that this mineralizing 

 operation is performed by means of heat or fufion j and there 

 is no perfon fkilled in chemiftry that will pretend to fay, this 

 may be done by aqueous folution. The combination of iron 

 and fulphur, for example, may eafily be performed by fufion j 



G g 2 but, 



