8. Wherefore we will proceed to take notice, that we also devis’d a way of trying whether or no Metalline Solutions though one of them at least had its Colour Adventitious, by the mixture of the Menstruum employ’d to dissolve it, might not be made to compound a Green after the manner of other Bodies. And though this seem’d not easie to be perform’d by reason of the Difficulty of finding Metalline Solutions of the Colour requisite, that would mix without Praecipitating each other; yet after a while having consider’d the matter, the first Tryal afforded me the following Experiment. I took a High Yellow Solution of good Gold in Aqua-Regis, (made of Aqua-fortis, and as I remember half its weight of Spirit of Salt) To this I put a due Proportion of a deep and lovely Blew Solution of Crude Copper, (which I have elsewhere taught to be readily Dissoluble in strong Spirit of Urine) and these two Liquors though at first they seem’d a little to Curdle one another, yet being throughly mingl’d by Shaking, they presently, as had been Conjectur’d, united into a Transparent Green Liquor, which continu’d so for divers days that I kept it in a small Glass wherein ’twas made, only letting fall a little Blackish Powder to the Bottom. The other Phaenomena of this Experiment belong not to this place, where it may suffice to take notice of the Production of a Green, and that the Experiment was more than once repeated with Success.
9. And lastly, to try whether this way of compounding Colours would hold ev’n in Ingredients actually melted by the Violence of the Fire, provided their Texture were capable of safely induring Fusion, we caus’d some Blew and Yellow Ammel to be long and well wrought together in the Flame of a Lamp, which being Strongly and Incessantly blown on them kept them in some degree of Fusion, and at length (for the Experiment requires some Patience as well as Skil) we obtain’d the expected Ammel of a Green Colour.
I know not, Pyrophilus, whether it be worth while to acquaint you with the ways that came into my Thoughts, whereby in some measure to explicate the first of the mention’d ways of making a Green; for I have sometimes Conjectur’d, that the mixture of the Bise and the Orpiment produc’d a Green by so altering the Superficial Asperity, which each of those Ingredients had apart, that the Light Incident on the mixture was Reflected with differing Shades, as to Quantity, or Order, or both, from those of either of the Ingredients, and such as the Light is wont to be Modify’d with, when it Reflects from Grass, or Leaves, or some of those other Bodies that we are wont to call Green. And sometimes too I have doubted, whether the produced Green might not be partly at least deriv’d from this, That the Beams that Rebound from the Corpuscles of the Orpiment, giving one kind of stroak upon the Retina, whose Perception we call Yellow, and the Beams Reflected from the Corpuscles of the Bise, giving another stroak upon the same Retina,