Experiment XVIII
But here, Pyrophilus, I muſt advertiſe you, that ’tis not every Yellow and every Blew that being mingl’d will afford a Green; For in caſe one of the Ingredients do not Act only as endow’d with ſuch a Colour, but as having a power to alter the Texture of the Corpuſcles of the other, ſo as to Indiſpoſe them to Reflect the Light, as Corpuſcles that exhibit a Blew or a Yellow are wont to Reflect it, the emergent Colour may be not Green, but ſuch as the change of Texture in the Corpuſcles of one or both of the Ingredients qualifies them to ſhew forth; as for inſtance, if you let fall a few Drops of Syrrup of Violets upon a piece of White Paper, though the Syrrup being ſpread will appear Blew, yet mingling with it two or three Drops of the lately mention’d Solution of Gold, I obtain’d not a Green but a Reddiſh mixture, which I expected from the remaining Power of the Acid Salts abounding in the Solution, ſuch Salts or Saline Spirits being wont, as we ſhall ſee anon, though weakn’d, ſo to work upon that Syrrup as to change it into a Red or Reddiſh Colour. And to confirm that for which I allege the former Experiment, I ſhall add this other, that having made a very ſtrong and high-colour’d Solution of Filings of Copper with Spirit of Urine, though the Menſtruum ſeem’d Glutted with the Metall, becauſe I put in ſo much Filings that many of them remain’d for divers days Undiſſolv’d at the Bottom, yet having put three or four Drops of Syrrup of Violets upon White Paper, I found that the deep Blew Solution proportionably mingl’d with this other Blew Liquor did not make a Blew mixture, but, as I expected, a fair Green, upon the account of the Urinous Salt that was in the Menſtruum.