4. And you may remember, that we obſerv'd a Green to be produc'd, when in the ſame Darkn'd Room we look'd at the Hole at which alone the Light enter'd, through the Green and Yellow parts of a ſheet of Marbl'd Paper laid over one another.
5. We found too, that the Beams of the Sun being trajected through two pieces of Glaſs, the one Blew and the other Yellow, laid over one another, did upon a ſheet of White paper on which they were made to fall, exhibit a lovely Green.
6. I hope alſo, that you have not already forgot, what was ſo lately deliver'd, concerning the compoſition of a Green, with a Blew and Yellow; of which moſt Authors would call the one a Real, and the other an Emphatical.
7. And I preſume, you may have yet freſh in your memory, what the fourteenth Experiment informs you, concerning the exhibiting of a Green, by the help of a Blew and Yellow, that were both of them Emphatical.
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 Præcipitating 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 Phænomena 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, like to Objects that are Blew, the Contiguity and Minuteneſs of theſe Corpuſcles may make the Appulſe of the Reflected Light fall upon the Retina within ſo narrow a Compaſs, that the part they Beat upon being but as it were a Phyſical point, they may give a Compounded ſtroak, which may conſequently exhibit a Compounded and new Kind of Senſation, as we ſee that two Strings of a Muſical Inſtrument being ſtruck together, making two