Page:Theophrastus - History of Stones - Hill (1774).djvu/350

 Pliny decribes by, Quorum extremus igniculus in flavedinem exeat. The Solution in Spirit of Nitre is of the true Emerald Colour, and extremely bright and vivid; and each of the others reembles very exactly the Colour of a particular Gem of the ame Clas; the firt of them being perfectly of the Colour of the yellowih green Praius, and the third of the Smaragdo-praius.

Thee Colours are each of them very beautiful; and that of the Solution in Agua regia is no other than what mut be expected, when we know the Colours of the other two, the Spirits of Salt and Nitre being imple Mentruums, and affording a green, and a yellowih green Solution; and the Agua regia, a compound Mentruum, partaking of the Nature of both the others, it mut naturally give a Solution of a Colour between both, that is a Green with les Yellow than that of the Spirit of Salt.

But though thee three acid Mentruums afford green Solutions of this Metal, it is too haty a Concluion to infer from thence, that all the Acid Mentruums will therefore do the ame; for Solutions of Copper in Oil of Vitriol, Oil of Sulphur, and Agua fortis, are all blue. They are in different Degrees, tho' all nearly approaching to each other, and the deepet of them not darker than that of the common Turquoies. Thee Solutions have alo this peculiar Property, that they immediately precipitate their Copper on Iron, if immered in them;