Page:Theophrastus - History of Stones - Hill (1774).djvu/348

 determinately reduced into Method at all: The different Acids having the Properties talked of in the Alkalies, of producing different Colours; and even the ame Acid being ometimes capable of affording either a green or a blue Solution, according to the different Quantity of the Metal diolved in it. In Caes of this Kind, however, I have every where judged the mot perfect Solution the properet to decribe the Effect of the Mentruum by: And of what I have principally learnt by thee Experiments, be pleaed to accept the following Account.

A Solution of Copper in Oil of Olives, is of a fine gras Green; in white Wax, of a bluih Green, approaching to the Colour of our Aqua marine; and in pure Water, of a dead whitih Green. In regard to thee Mentruums it is, however, to be oberved, that the expreed vegetable Oils do not diolve Copper, as Oils, but by means of certain other heterogene Particles which they contain; for all expreed vegetable Oils contain in them Water, and a latent acid Salt: of both which, I am pretty certain, they may be wholly diveted by Fire, and rendered, by that Means, incapable of acting as Mentruums on this Metal: For I have found, that Oil of Olives, after long boiling, has been capable of extracting carce any Colour at all from Copper; and make no doubt but that it might be o perfectly deprived of its Acid, as well as Water, by long boiling with Litharge, or ome imilar Subtance proper