PHYSICAL ann LITERARY. 331 
are not perceptible fingly, even when viewed 
thro’.a pretty good lens; yet they muft be | 
_ fimilar to one another, and retain the proper- 
4a tles of real nitre. acilsh.) 
. Ler us: next confider the effects of an- 
_ other liquor, upon the fame falt-petre. 
2 _- Ir oil of vitriol is poured upon a- parcel 
of nitre, there happens likewife a folution, 
but with appearances different from thofe in 
the former; for this is accompanied with a 
confiderable inteftine motion and expanfion,. 
fmoak and heat, and produces a much great- 
er change on the nitre: for; by the help of 
external heat and clofe veffels,, there .rife 
_ from the mixture copious red fteams, which 
are condenfed into a corrofive acid; liquor, »ve- 
_ ry active and. volatile, and there is left a 
white (aline mafs, no way refembling nitre.. 
«From what -has been: faid formerly ‘of 
this ‘experiment, it appears that the oil of 
- vitriol makes a more minute and fubtile: di- 
- vifion of nitre than what fimple water can’ 
_ do; that the fluid acid falt'of the oil of vi- 
— triol attraétsione part of each real particle of 
_nitre, v/z. the fixt and alcaline bafis, while 
this fame vitriolic acid feems to repell another 
 patt of nitre, that is the acid and volatile 
Bron. part, 
‘ 
