Aving promis'd in the [114], and [115]. Pages of the foregoing Discourse of Whiteness and Blackness, to shew, that those two Colours may by a change of Texture in bodies, each of them apart Diaphanous and Colourless, be at pleasure and in a trice as well Generated as Destroy'd, We shall begin with Experiments that may acquit us of that promise.
Take then what Quantity you please of Fair Water, and having Heated it, put into it as much good Common Sublimate, as it is able to Dissolve, and (to be sure of having
it well glutted:) continue putting in the Sublimate, till some of it lye Untouch'd in the bottom of the Liquor, Filter this Solution through Cap-paper, to have it cleer and limpid, and into a spoonfull or two thereof, (put into a clean glass vessel,) shake about four or five drops (according as you took more or less of this Solution) of good limpid Spirits of Urine, and immediately the whole mixture will appear White like Milk, to which mixture if you presently add a convenient proportion of Rectifi'd Aqua Fortis (for the number of drops is hard to determine, because of the Differing Strength of the liquor, but easily found by tryal) the Whiteness will presently disappear, and the whole mixture become Transparent, which you may, if you please, again reduce to a good degree of Whiteness (though inferiour to the first) onely by a more copious affusion of fresh Spirit of Urine. N. First, That it is not so necessary to employ either Aqua Fortis or Spirit of Urine about this Experiment, but that we have made it with other liquors instead of these, of which perhaps more elsewhere. Secondly, That this Experiment, though not made with the same Menstruums, nor producing the same Colour is yet much of Kin to that other to be
mentioned in this Tract among our other Experiments of Colours, about turning a Solution of Præcipitate into an Orange-colour, and the Chymical Reason being much alike in both, the annexing it to one of them may suffice FOR both.
EXPERIMENT II.
Make a strong Infusion of broken Galls in Fair Water, and having Filtred it into a clean Vial, add more of the same liquor to it, till you have made it somewhat Transparent, and sufficiently diluted the Colour, for the credit of the Experiment, lest otherwise the Darkness of the liquor might make it be objected, that 'twas already almost Ink; Into this Infusion shake a convenient quantity of a Cleer, but very strong Solution of Vitriol, and you shall immediately see the mixture turn Black almost like Ink, and such a way of producing Blackness is vulgar enough; but if presently after you doe upon this mixture drop a small quantity of good oyl of Vitriol, and, by shaking the Vial disperse it nimbly through the two other liquors, you shall (if you perform your part well, and have employ'd oyl of Vitriol Cleer and Strong enough) see the Darkness of the liquor presently begin
to be discuss'd, and grow pretty Cleer and Transparent, losing its Inky Blackness, which you may again restore to it by the affusion of a small quantity of a very strong Solution of Salt of Tartar. And though neither of these Atramentous liquors will seem other than very Pale Ink, if you write with a clean Pen dipt in them, yet that is common to them with some sorts of Ink that prove very good when Dry, as I have also found, that when I made these carefully, what I wrote with either of them, especially with the Former, would when throughly Dry grow Black enough not to appear bad Ink. This Experiment of taking away and restoring Blackness from and to the liquors, we have likewise tryed in Common Ink; but there it succeeds not so well, and but very slowly, by reason that the Gum wont to be employed in the making it, does by its Tenacity oppose the operations of the above mention'd Saline liquors. But to consider Gum no more, what some kind of Præcipitation may have to do in the producing and destroying of Inks without it, I have elsewhere given you some occasion and assistance to enquire; But I must not now stay to do so my self, only I shall take notice to you, that though it be taken for granted that bodies will not be Præcipitated by Alcalizat Salts,
that have not first been dissolved in some Acid Menstruums, yet I have found upon tryals, which my conjectures lead me to make on purpose, That divers Vegetables barely infus'd, or, but slightly decocted in common water, would, upon the affusion of a Strong and Cleer Lixivium of Potashes, and much more of some other Præcipitating liquors that I sometimes employ, afford good store of a Crudled matter, such as I have had in the Præcipitations of Vegetable substances, by the intervention of Acid things, and that this matter was easily separable from the rest of the liquor, being left behind by it in the Filtre; and in making the first Ink mention'd in this Experiment, I found that I could by Filtration separate pretty store of a very Black pulverable substance, that remain'd in the Filtre, and when the Ink was made Cleer again by the Oyl of Vitriol, the affusion of dissolv'd Sal Tartari seem'd but to Præcipitate, and thereby to Unite and render Conspicuous the particles of the Black mixture that had before been dispers'd into very Minute and singly Invisible particles by the Incisive and resolving power of the highly Corrosive Oyl of Vitriol.
And to manifest, Pyrophilus, that Galls are not so requisite as many suppose to the making Atramentous Liquors, we have sometimes made the following Experiment, We took dryed Rose leaves and Decocted them for a while in Fair Water, into two or three spoonfulls of this Decoction we shook a few drops of a strong and well filtrated Solution of Vitriol (which perhaps had it been Green would have done as well) and immediately the mixture did turn Black, and when into this mixture presently after it was made, we shook a just Proportion of Aqua Fortis, we turn'd it from a Black Ink to a deep Red one, which by the affusion of a little Spirit of Urine may be reduc'd immediately to an Opacous and Blackish Colour. And in regard, Pyrophilus, that in the former Experiments, both the Infusion of Galls, and the Decoction of Roses, and the Solution of Copperis employ'd about them, are endow'd each of them with its own Colour, there may be a more noble Experiment of the sudden production of Blackness made by the way mention'd in the Second Section of the Second Part of our Essays, for though upon the Confusion of the two Liquors there mention'd, there do immediately emerge a very Black mixture, yet both the Infusion of Orpiment and the Solution of Minium were before their being joyn'd together, Limpid and Colourless.