you, that in a noted Colour-shop, I brought them by Questions to confess to me, that they made their Sap-green much after the ways by our Botanist here mention’d.  And on this occasion I shall add an Observation, which though it does not strictly belong to this place, may well enough be mention’d here, namely, that I find by an account given us by the Learned Clusius, of Alaternus, that ev’n the Grosser Parts of the same Plant, are some of them one Colour, and some another; For speaking of that Plant, he tells us, that the Portugalls use the Bark to Dye their Nets into a Red Colour, and with the Chips of the Wood, which are Whitish, they Dye a Blackish Blew.

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