292 appendix. 
Experiment IV. 
X. TT was found in Experiment XCVI. Vol. 
X I. p. 224. chat the Walton Pyrites, which 
is a vitriolic Stone, abforbed more Air than 
it generated, with compound Aqua-fortis a- 
lone, and generated more than it abforbed, 
when diluted with an equal Quantity of Wa- 
ter. But it is not the fame with the vitriolic 
Pyrites which is gathered on the Sea Shore 
near fVhitJlablcmKenty of which Stones green 
Vitriol or Coperas are there made; for when on 
five hundred and twenty five Grains or half 
a cubic Inch of it powdered, a cubic Inch of 
compound Aqva-fortis was poured, it expand- 
ed with a red Fume into a Space equal to two 
hundred and fixteen cubic Inches, but in two 
Hours time that Space was wholly contraded, 
and a hundred and eight cubic Inches of Air 
were abforbed. And the Fumes of this Py- 
rites were of fo ftrongly abforbing a Quality, 
that when the Aqna-fortis w^as diluted with 
thrice its Quantity of Water, its Fumes ab- 
forbed a hundred and forty four cubic Inches 
of Air more than was generated. 
6 
z. That 
