Melted with Zink, they make an uniform Maſs of a fine gold Colour, as they do Braſs with Calamine.
Held over melted Orpiment, they become not only white but brittle.
And by extreme Violence of Fire, are converted into a hard, denſe, glaſſy Matter, of a deep Red; tranſparent, and in ſome Degree reſembling the Sorane Garnet.
It has been the general Opinion of the Chemiſts, that Solutions of this Metal in Acids were green, and in Alkalies blue: Some, however have altered, from a few Experiments of their own, or perhaps only from what they imagined muſt have been the Succeſs of Experiments, this general Account; and particularly among certain of the more modern Writers, it has ſtood, that Copper, diſſolved in Acids or fixed Alkalies, affords a green Colour; and in volatile Alkalies, a fine Blue: But you will obſerve, by the following Experiments, that theſe Accounts are neither of them to be depended on: And, indeed, whoever has Diſquiſitions of this Kind to attempt, will always find, that it muſt be a Knowledge of Nature, and not of Books, that will afford him what he can depend on; and that Syſtems built on any Body's Experiments but his own, will be found to ſtand on a very infirm Baſis.
What I have been able to learn, by repeated Experiments on this Metal in Menſtrums of all Kinds, is, that the Solutions of it in different Fluids, cannot be, in regard to Colour,
determinately
