Experiment III
If pieces of White Harts-horn be with a competent degree of Fire diſtill’d in a Glaſs-retort, they will, after the avolation of the Flegm, Spirit, Volatile Salt, and the looſer and lighter parts of the Oleagenous ſubſtance, remain behind of a Cole-black colour. And even Ivory it ſelf being skilfully Burnt (how I am wont to do it, I have elſewhere ſet down) affords Painters one of the beſt and deepeſt Blacks they have, and yet in the Inſtance of diſtill’d Harts-horn, the operation being made in Glaſs-veſſels carefully clos’d, it appears there is no Extraneous Black ſubſtance that Inſinuates it ſelf into White Harts-horn, and thereby makes it turn Black; but that the Whiteneſs is deſtroy’d, and the Blackneſs generated, only by a Change of Texture, made in the burnt Body, by the Receſs of ſome parts and the Tranſpoſition of others. And though I remember not that in many Diſtillations of Harts-horn I ever ſound the Cap. Mort. to paſs from Black to a true Whiteneſs, whilſt it continu’d in Clos’d veſſels, yet having taken out the Cole-black fragments, and Calcin’d them in Open veſſels, I could in few hours quite deſtroy that Blackneſs, & without ſenſibly changing their Bulk or Figure, reduce them to great Whiteneſs. So much do theſe two Colours depend upon the Diſpoſition of the little parts, that the Bodies wherein they are to be met with do conſiſt of. And we find, that if Whitewine Tartar, or even the white Cryſtalls of ſuch Tartar be burnt without being truly Calcin’d, the Cap. Mortuum (as the Chymiſts call the more Fixt part) will be Black. But if you further continue the Calcination till you have perfectly Incinerated the Tartar, & kept it long enough in a Strong fire, the remaining Calx will be White. And ſo we ſee that not only other Vegetable ſubſtances, but even White woods, as the Hazel, will yield a Black Charcoal, and afterwards Whitiſh aſhes; And ſo Animal ſubſtances naturally White, as Bones and Eggſhels, will grow Black upon the being Burnt, and White again when they are perfectly Calcin’d.