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
