and^oDtltttOnofCJolattlttp. 53 

 this Confideration I (hall here ob- 

 lerve to you, fince I did not doe it at 

 my entrance on thefe Notes, that 

 Chymifts are wont to fpeak, and I 

 have accordingly been led to treaty 

 of Volatility and Fixity in a popular 

 fenfe of thofe Terms* For if we 

 would confider the matter more 

 ftri&ly , I prefume we fhould find 

 that Volatility and Fixity are but re- 

 lative Qualities, which are to be efti- 

 mated, efpecially the former of them, 

 by the degree of fire to which the 

 body, whereto we afcribe one or 

 other of thofe Qualities, is expofed , 

 and therefore it is much more difficult 

 than men are aware of 5 to determine; 

 accurately , when a body ought to 

 be accounted Volatile and when not> 

 fince there is no determinate degree 

 of Heat agreed on, nor indeed eafie 

 to be deviled, that may be as a ftan- 

 dard 5 whereby to meafure Volatility 

 and Fixtnefs : And 'tis obvious, that 

 a body, that remains fixt in one de- 

 gree of fire, may be forced up by a- 

 nother. To which may be added, 



agree- 



