372 ESSAYS AND OBSERVATIONS 



their mutual attra(flion. Laflly, it is evi- 

 dent, from the above appearances, that 

 though the parts of nitre which fwim in 

 the water are fo fmall, that they are not 

 perceptible fingly, even when viewed 

 through a pretty good lens ; yet they 

 muft be fimilar to one another, and re- 

 tain the properties of real nitre. 



Let us next confider the effeds of an- 

 other liquor,, upon the fame fait petre. 



If oil of vitriol is poured upon a par- 

 cel of nitre, there happens likewife a fo- 

 lution, but with appearances different 

 from thofe in the former ; for this is ac- 

 companied with a confiderable inteftine 

 m.otion and expanfion, fmoak and heat, 

 and produces a much greater change on 

 the nitre : For, by the help of external 

 heat and clofe vefTels, there rife from the 

 mixture copious red fleams, which are 

 condenfed into a corrofrve acid liquor, ve- 

 ry a(5live and volatile; and there is left a 

 white faline mafs, no way refembling ni- 

 tre- 



From what has been faid formerly of 

 this experiment, it appears that the oil of 



vitriol 



