The greatest difficulty that I find against this Hypothesis, is, that there seem to be more distinct colours then two, that is, then Yellow and Blue. This Objection is grounded on this reason, that there are several Reds, which diluted, make not a Saffron or pale Yellow, and therefore Red, or Scarlet seems to be a third colour distinct from a deep degree of Yellow.
To which I answer, that Saffron affords us a deep Scarlet tincture, which may be diluted into as pale a Yellow as any, either by making a weak solution of the Saffron, by infusing a small parcel of it into a great quantity of liquor, as in spirit of Wine, or else by looking through a very thin quantity of the tincture, and which may be heightn’d into the loveliest Scarlet, by looking through a very thick body of this tincture, or through a thinner parcel of it, which is highly impregnated with the tinging body, by having had a greater quantity of the Saffron dissolv’d in a smaller parcel of the liquor.
Now, though there may be some particles of other tinging bodies that give a lovely Scarlet also, which though diluted never so much with liquor, or looked on through never so thin a parcel of ting’d liquor, will not yet afford a pale Yellow, but onely a kind of faint Red; yet this is no argument but that those ting’d particles may have in them the faintest degree of Yellow, though we may be unable to make them exhibit it; For that power of being diluted depending upon the divisibility of the ting’d body, if I am unable to make the tinging particles so thin as to exhibit that colour, it does not therefore follow, that the thing is impossible to be done; now, the tinging particles of some bodies are of such a nature, that unless there be found some way of comminuting them into less bulks then the liquor does dissolve them into, all the Rays that pass through them must necessarily receive a tincture so deep, as their appropriate refractions and bulks compar’d with the proprieties of the dissolving liquor must necessarily dispose them to empress, which may perhaps be a pretty deep Yellow, or pale Red.
And that this is not gratis dictum, I shall add one instance of this kind, wherein the thing is most manifest.
If you take Blue Smalt, you shall find, that to afford the deepest Blue, which cæteris paribus has the greatest particles or sands; and if you further divide, or grind those particles on a Grindstone, or porphyry stone, you may by comminuting the sands of it, dilute the Blue into as pale a one as you please, which you cannot do by laying the colour thin; for wheresoever any single particle is, it exhibits as deep a Blue as the whole mass. Now, there are other Blues, which though never so much ground, will not be diluted by grinding, because consisting of very small particles, very deeply ting’d, they cannot by grinding be actually separated into smaller particles then the operation of the fire, or some other dissolving menstruum, reduc’d them to already.
Thus all kind of Metalline colours, whether precipitated, sublim’d, calcin’d, or otherwise prepar’d, are hardly chang’d by grinding, as ultra marine is not more diluted; nor is Vermilion or Red-lead made of a more faint colour by grinding; for the smallest particles of these which I have view’d with my greatest Magnifying-Glass, if they be well enlightned, appear very deeply ting’d with their peculiar colours; nor, though I have magnified and enlightned the particles exceedingly, could I in many of them, perceive them to be transparent, or to be whole particles, but the smallest specks that I could find among well ground Vermilion and Red-lead, seem’d to be a Red mass, compounded of a multitude of less and less motes, which sticking together, compos’d a bulk, not one thousand thousandth part of the smallest visible sand or mote.
And this I find generally in most Metalline colours, that though they consist of parts so exceedingly small, yet are they very deeply ting’d, they being so ponderous, and having such a multitude of terrestrial particles throng’d into a little room; so that ’tis difficult to find any particle transparent or resembling a pretious stone, though not impossible; for I have observ’d divers such shining and resplendent colours intermixt with the particles of Cinnaber, both natural and artificial, before it hath been ground and broken or flaw’d into Vermilion: As I have also in Orpiment, Red-lead, and Bise, which makes me suppose, that those metalline colours are by grinding, not onely broken and separated actually into smaller pieces, but that they are also flaw’d and brused, whence they, for the most part, become opacous, like flaw’d Crystal or Glass, &c. But for Smalts and verditures, I have been able with a Microscope to perceive their particles very many of them transparent.
Now, that the others also may be transparent, though they do not appear so to the Microscope, may be made probable by this Experiment: that if you take ammel that is almost opacous, and grind it very well on a Porphyry, or Serpentine, the small particles will by reason of their flaws, appear perfectly opacous; and that ’tis the flaws that produce this opacousness, may be argued from this, that particles of the same Ammel much thicker if unflaw’d will appear somewhat transparent even to the eye; and from this also, that the most transparent and clear Crystal, if heated in the fire, and then suddenly quenched, so that it be all over flaw’d, will appear opacous and white.
And that the particles of Metalline colours are transparent, may be argued yet further from this, that the Crystals, or Vitriols of all Metals, are transparent, which since they consist of metalline as well as saline particles, those metalline ones must be transparent, which is yet further confirm’d from this, that they have for the most part, appropriate colours; so the vitriol of Gold is Yellow; of Copper, Blue, and sometimes Green; of Iron, green; of Tinn and Lead, a pale White; of Silver, a pale Blue, &.
And next, the Solution of all Metals into menstruums are much the same with the Vitriols, or Crystals. It seems therefore very probable, that those colours which are made by the precipitation of those particles out of the menstruums by transparent precipitating liquors should be transparent also. Thus Gold precipitates with oyl of Tartar, or spirit of Urine into a brown Yellow, Copper with spirit of Urine into a Mucous blue, which retains its transparency. A solution of sublimate (as the same Illustrious Authour I lately mention’d shews in his 40. Experiment) precipitates with oyl of Tartar per deliquium, into an Orange colour’d precipitate; nor is it less probable, that the calcination of those Vitriols by the fire, should have their particles transparent: Thus Saccarum Saturni, or the Vitriol of Lead by calcination becomes a deep Orange-colour’d minium, which is a kind of precipitation by some Salt which proceeds from the fire; common Vitriol calcin’d, yields a deep Brown Red, &c.