Page:Theophrastus - History of Stones - Hill (1774).djvu/340

 Zaffer, there is in the Arguments founded on its uppoed Effects.

And to the Firt, That the Turquoie and Sapphire are coloured by the ame Matter, and that this Matter is univerally allowed to be a native Zaffer: I hall anwer, That I allow the Sapphire and Turquoie to be coloured by Particles of the ame Kind; that I know it to be the common Opinion, that the Turquoie is coloured by Zaffer, and not by Copper: But that I alo know it to be an erroneous one. I know the Turquoie owes its Colour to Copper only; having ucceeded in a Coure of Experiments, by which I have been able to divet the Turquoie wholly of its Colour; to precipitate and preerve that Colour eparate and alone; to prove that Colour, by the Effects of different Mentruums, to be abolute Copper; and, by Experiments founded on this Proces, to give, by a Solution of Copper in a volatile Alkali, the true Turquoie Colour to the Subtance of the native Turquoies, which is abolutely no other than animal Bone; and to make, by that means, thoe factitious Turquoies, which have been put, before a judicious Aembly, to the everet Trials; and gave all the Marks of the genuine.

To the Second Argument, That Copper is not capable of giving o deep a Blue as that of ome of thee Gems; I have a Solution of Copper, the very one with which I tained the factitious Turquoies, which is of the true Colour of