To summ up all therefore in a word, I have not yet found any solid colour’d body, that I have yet examin’d, perfectly opacous; but those that are least transparent are Metalline and Mineral bodies, whose particles generally, seeming either to be very small, or very much flaw’d, appear for the most part opacous, though there are very few of them that I have look’d on with a Microscope, that have not very plainly or circumstantially manifested themselves transparent.
And indeed, there seem to be so few bodies in the world that are in minimis opacous, that I think one may make it a rational Query, Whether there be any body absolutely thus opacous? For I doubt not at all (and I have taken notice of very many circumstances that make me of this mind) that could we very much improve the Microscope, we might be able to see all those bodies very plainly transparent, which we now are fain onely to ghess at by circumstances. Nay, the Object Glasses we yet make use of are such, that they make many transparent bodies to the eye, seem opacous through them, which if we widen the Aperture a little, and cast more light on the objects, and not charge the Glasses so deep, will again disclose their transparency.
Now, as for all kinds of colours that are dissolvable in Water, or other liquors, there is nothing so manifest, as that all those ting’d liquors are transparent; and many of them are capable of being diluted and compounded or mixt with other colours, and divers of them are capable of being very much chang’d and heightned, and fixt with several kinds of Saline menstruums. Others of them upon compounding, destroy or vitiate each others colours, and precipitate, or otherwise very much alter each others tincture. In the true ordering and diluting, and deepning, and mixing, and fixing of each of which, consists one of the greatest mysteries of the Dyers; of which particulars, because our Microscope affords us very little information, I shall add nothing more at present; but onely that with a very few tinctures order’d and mixt after certain ways, too long to be here set down, I have been able to make an appearance of all the various colours imaginable, without at all using the help of Salts, or Saline menstruums to vary them.
As for the mutation of Colours by Saline menstruums, they have already been so fully and excellently handled by the lately mention’d Incomparable Authour, that I can add nothing, but that of a multitude of trials that I made, I have found them exactly to agree with his Rules and Theories; and though there may be infinite instances, yet may they be reduc’d under a few Heads, and compris’d within a very few Rules. And generally I find, that Saline menstruums are most operative upon those colours that are Purple, or have some degree of Purple in them, and upon the other colours much less. The spurious pulses that compose which, being (as I formerly noted) so very neer the middle between the true ones, that a small variation throws them both to one side, or both to the other, and so consequently must make a vast mutation in the formerly appearing Colour.
Observ. [XI]. Of Figures observ’d in small Sand.
Sand generally seems to be nothing else but exceeding small Pebbles, or at least some very small parcels of a bigger stone; the whiter kind seems through the Microscope to consist of small transparent pieces of some pellucid body, each of them looking much like a piece of Alum, or Salt Gem; and this kind of Sand is angled for the most part irregularly, without any certain shape, and the granules of it are for the most part flaw’d, through amongst many of them it is not difficult to find some that are perfectly pellucid, like a piece of clear Crystal, and divers likewise most curiously shap’d, much after the manner of the bigger Stiriæ of Crystal, or like the small Diamants I observ’d in certain Flints, of which I shall by and by relate; which last particular seems to argue, that this kind of Sand is not made by the comminution of greater transparent Crystaline bodies, but by the concretion or coagulation of Water, or some other fluid body.
There are other kinds of courser Sands, which are browner, and have their particles much bigger; these, view’d with a Microscope, seem much courser and more opacous substances, and most of them are of some irregularly rounded Figures; and though they seem not so opacous as to the naked eye, yet they seem very foul and cloudy, but neither do these want curiously transparent, no more than they do regularly figur’d and well colour’d particles, as I have often found.
There are multitudes of other kinds of Sands, which in many particulars, plainly enough discoverable by the Microscope, differ both from these last mention’d kinds of Sands, and from one another: there seeming to be as great variety of Sands, as there is of Stones. And as amongst Stones some are call’d precious from their excellency, so also are there Sands which deserve the same Epithite for their beauty; for viewing a small parcel of East-India Sand (which was given me by my highly honoured friend, Mr. Daniel Colwall) and, since that, another parcel, much of the same kind, I found several of them, both very transparent like precious Stones, and regularly figur’d like Crystal, Cornish Diamants, some Rubies, &c. and also ting’d with very lively and deep colours, like Rubys, Saphyrs, Emeralds, &c. These kinds of granules I have often found also in English Sand. And ’tis easie to make such a counterfeit Sand with deeply ting’d Glass, Enamels and Painters colours.
It were endless to describe the multitudes of Figures I have met with in these kind of minute bodies, such as Spherical, Oval, Pyramidal, Conical, Prismatical, of each of which kinds I have taken notice.