PHYSICAL AND LITERARY. 40^ 



which I made the preceeding experiments, 

 had run over nothing at all, after its exit 

 from the fpring, but was taken up by 

 himfelf immediately as it iffued out of 

 the rock. Dr James Hunter, Phyfician in 

 Moffat, afterwards fent me fome of the 

 fame water, which he received into bot- 

 tles, by applying their mouth to the ori- 

 fice of the vein in the rock from which 

 it iflued ; and from it I obtained cryftals 

 oi 'uitriolum Mart is ^ which were of a paler 

 green than the artificial. 



In Auguft 1752, this fpaw, with fy- 

 fup of violets, flruck no green tindlure. 



With ol. tart. />. d. it immediately 

 turned green; and clouds of a deeper greei* 

 and more in quantity than in Auguft 

 1750, were formed, and that much foon- 

 er than in the preceeding experiments. 



With powder of galls, it fcarce chan- 

 ged its colour ; and, even after ftanding 

 fome time, it exhibited but a faint blue. 

 I was at a lofs for the reafon of its giving 

 fo faint a blue with galls j when, at the 

 fame time, I knew, by its immediately 



turn" 



