Experiment XIV
I took a piece of Black-horn, (poliſh’d as being part of a Comb) this with a piece of broken glaſs I ſcrap’d into many thin and curdled flakes, ſome ſhorter and ſome longer, and having laid a pretty Quantity of theſe ſcrapings together, I found, as I look’d for, that the heap they compos’d was White, and though, if I laid it upon a clean piece of White Paper, its Colour ſeem’d ſomewhat Eclips’d by the greater Whiteneſs of the Body it was compar’d with, looking ſomewhat like Linnen that had been ſulli’d by a little wearing, yet if I laid it upon a very Black Body, as upon a Beaver Hatt, it then appear’d to be of a good White, which Experiment, that you may in a trice make when you pleaſe, ſeems very much to Disfavour both their Doctrine that would have Colours to flow from the Subſtantial Forms of Bodyes, and that of the Chymiſts alſo, who aſcribe them to one or other of their three Hypoſtatical Principles; for though in our Caſe there was ſo great a Change made, that the ſame Body without being ſubſtantially either Increas’d or Leſſened, paſſes immediately from one extreme Colour to another (and that too from Black to White) yet this ſo great and ſudden change is effected by a ſlight Mechanical Tranſpoſition of parts, there being no Salt or Sulphur or Mercury that can be pretended to be Added or Taken away, nor yet any ſubſtantial Form that can reaſonably be ſuppos’d to be Generated and Deſtroy’d, the Effect proceeding only from a Local Motion of the parts which ſo vary’d their Poſition as to multiply their diſtinct Surfaces, and to Qualifie them to Reflect far more Light to the Eye, than they could before they were ſcrap’d off from the entire piece of Black horn.