Green Vitriol, or Engli/b Copperas . 8 5 
cult to account for : fince all mineral Sub- 
ftances, whofe Colour is blue or green, have 
been generally fuppofed to derive their Co¬ 
lour from Copper. 
When diffolved in Water, it conftantly 
drops to the Bottom a yellow ferrugi¬ 
nous Sediment ; which being taken away, 
the remaining Liquor, after a due Time of 
Reft, affords Cryftals much clearer and of 
a finer Green than the Vitriol was at firft. 
Thefe being diffolved again throw down 
another yellowifh Sediment, but in much 
lefs Quantity than before, and when cry- 
ftalized anew appear of a ftill more live¬ 
ly Colour. And by repeating this Operas 
tion, they may be rendered perfectly trans¬ 
parent and of a delightful Green; tho’ 
after all fome Iron will ftill be left, which 
Subjects them to contract a Ruft, if expofed 
to the open Air. 
A Drop of the Solution, moderately heat¬ 
ed, and applied to the Microfcope, be¬ 
gins to cryftalize about the Edges, and 
proceeds gradually, as the Figures 1, 2, 3. 
Plate II. N° 2. reprefent, under the Name 
of Green Vitriol. After waiting fome Time, 
the Configurations pufh out, fuddenly and 
haftily, towards the Middle, in the Man¬ 
ner reprefented by Figure 4, which begins 
at a, and thrufts forwards and fideways 
at the fame Inftant, with wonderful Order 
and Regularity, to the other Extremity b, 
G 3 where 
