m 



( 19 y { 



their Acceflion fhould as well corre& the 

 Form as augment the Matter of our An- 

 notations. And as for the two Tracts, 

 that are inferted among thefe Effays about 

 Qualities h I mean the Vijcourfe of the 1m- 

 perfeSion of the Chymical Vo&rine of them> 

 and the Reflexions on the Hjpothefis of 

 Acidum and Alcali , the occalion of their 

 being made parts of this Book is fo far 

 exprefs'd in the Tradfcs themfelvcs , that 

 I need not here trouble the Reader with 

 a particular Account of it. 



V. I do not undertake, that all the fol- 

 lowing Accounts of Particular Qualities 

 would prove to be the very true ones, nor 

 every Explication the beft that can be de- 

 vis'd. For befides that the difficulty of 

 the Subje6t , and Incompleatnefe of the 

 Hiftory we yet have of Qualifies , may 

 well deterre a man, lefs diffident of his 

 own abilities than I juftly am, from affu- 

 ming fo much to himfelf, it is not abfo- 

 lutely necefTary to my prefent Detign. 

 For, Mechanical Explications of natural 

 Phenomena do give fo much more fatis- 

 fa&ion to ingenious minds , than thofe 

 that nouft employ Substantial Forms , Sym- 

 pathy, Antipathy , &c. that the more judi- 

 cious of the vulgar Philofophers them- 

 fclves prefer them before all others, when 

 they can be had i (as iselfewhere (hewn 



at 



