Annotation III.
And on this occasion (Pyrophilus) I must here (having forgot to do it sooner) advertise you once for all, that having written several of the foregoing Experiments, not only in haste but at seasons of the year, and in places wherein I could not furnish my self with such Instruments, and such a variety of Materials, as the design of giving you an Introduction into the History of Colours requir'd, it can scarce be otherwise but that divers of the Experiments, that I have set down, may afford you some matter of new Tryals, if you think fit to supply the deficiencies of some of them (especially the freshly mention'd about Lakes, and those that concern Emphatical Colours) which deficiencies for want of being befriended with accommodations I could better discern than avoid.
Annotation IV.
The use of Allom is very great as well as familiar in the Dyers Trade, and I have not been ill pleas'd with the use I have been able to make of it in preparing other pigments than those they imploy with Vegetable Juices. But the Lucriferous practises of Dyers and other Tradesmen, I do, for Reasons that you may know when you please, purposely forbear in this Essay, though not strictly from pointing at, yet from making it a part of my present work explicitly and circumstantially to deliver, especially since I now find (though late and not without some Blushes at my prolixity) that what I intended but for a short Essay, is already swell'd into almost a Volume.
EXPERIMENT L.
Yet here, Pyrophilus, I must take leave to insert an Experiment, though perhaps you'l think its coming in here an Intrusion, For I confess its more proper place would have been among those Experiments, that were brought as proofs and applications of our Notions concerning the differences of
Salts; but not having remembred to insert it in its fittest place, I had rather take notice of it in this, than leave it quite unmention'd: partly because it doth somewhat differ from the rest of our Experiments about Colours, in the way whereby 'tis made; and partly because the grounds upon which I devis'd it, may hint to you somewhat of the Method I use in Designing and Varying Experiments about Colours, and upon this account I shall inform you, not only What I did, but Why I did it.
I consider'd then that the work of the former Experiments was either to change the Colour of a Body into another, or quite to destroy it, without giving it a successor, but I had a mind to give you also a way, whereby to turn a Body endued with one Colour into two Bodies, of Colours, as well as consistencies, very distinct from each other, and that by the help of a Body that had it self no Colour at all. In order to this, I remembred, that finding the Acidity of Spirit of Vinegar to be wholly destroy'd by its working upon Minium (or calcin'd Lead) whereby the Saline particles of the Menstruum have their Taste and Nature quite alter'd, I had, among other Conjectures I had built upon that change, rightly concluded, that the Solution of Lead
in Spirit of Vinegar would alter the Colour of the Juices and Infusions of Several Plants, much after the like manner that I had found Oyl of Tartar to do; and accordingly I was quickly satisfied upon Tryal, that the Infusion of Rose-leaves would by a small quantity of this Solution well mingl'd with it, be immediately turn'd into a somewhat sad Green.