Experiment XXX
Among the Experiments that tend to ſhew that the change of Colours in Bodies may proceed from the Vary’d Texture of their Parts, and the conſequent change of their Diſpoſition to Reflect or Refract the Light, that ſort of Experiments muſt not be left unmention’d, which is afforded us by Chymical Digeſtions. For, if Chymiſts will believe ſeveral famous Writers about what they call the Philoſophers Stone, they muſt acknowledge that the ſame Matter, ſeald up Hermetically in a Philoſophical Egg, will by the continuance of Digeſtion, or if they will have it ſo (for it is not Material in our caſe which of the two it be) of Decoction, run through a great Variety of differing Colours, before it come to that of the Nobleſt Elixir; whether that be Scarlet, or Purple, or what ever other Kind of Red. But without building any thing on ſo Obtruſe and Queſtionable an Operation, (which yet may be pertinently repreſented to thoſe that believe the thing) we may obſerve, that divers Bodies digeſted in carefully-clos’d Veſſels, will in tract of time, change their Colour: As I have elſewhere mention’d my having obſerv’d ev’n in Rectify’d Spirit of Harts-horn, and as is evident in the Precipitations of Amalgams of Gold, and Mercury, without Addition, where by the continuance of a due Heat the Silver-Colour’d Amalgam is reduc’d into a ſhining Red Powder. Further Inſtances of this Kind you may find here and there in divers places of my other Eſſays. And indeed it has been a thing, that has much contributed to deceive many Chymiſts, that there are more Bodies than one, which by Digeſtion will be brought to exhibit that Variety and Succeſſion of Colours, which they imagine to be Peculiar to what they call the True matter of the Philoſophers. But concerning this, I ſhall referr you to what you may elſewhere find in the Diſcourſe written touching the paſſive Deceptions of Chymiſts, and more about the Production of Colours by Digeſtion you will meet with preſently. Wherefore I ſhall now make only this Obſervation from what has been deliver’d, That in theſe Operations there appears not any cauſe to attribute the new Colours emergent to the Action of a new Subſtantial form, nor to any Increaſe or Decrement of either the Salt, Sulphur, or Mercury of the Matter that acquires new Colours: For the Veſſels are clos’d, and theſe Principles according to the Chymiſts are Ingenerable and Incorruptible; ſo that the Effect ſeems to proceed from hence, that the Heat agitating and ſhuffling the Corpuſcles of the Body expos’d to it, does in proceſs of time ſo change its Texture, as that the Tranſpoſed parts do Modifie the incident Light otherwiſe, than they did when the Matter appear’d of another Colour.