t would be to such as are troubled with the Stone,
to find some _menstruum_ might dissolve them without hurting the Bladder,
is easily imagin'd, since some _injections_ made of such bodies might
likewise dissolve the stone, which seems much of the same nature.

It may therefore, perhaps, be worthy some Physicians enquiry, whether there
may not be something mixt with the Urine in which the Gravel or Stone lies,
which may again make it dissolve it, the first of which seems by it's
regular Figures to have been sometimes _Crystalliz'd_ out of it. For
whether this _Crystallization_ be made in the manner as _Alum_, _Peter_,
&c. are _crystallized_ out of a cooling liquor, in which, by boyling they
have been dissolv'd; or whether it be made in the manner of _Tartarum
Vitriolatum_, that is, by the _Coalition_ of an _acid_ and a _Sulphureous_
substance, it seems not impossible, but that the liquor it lies in, may be
again made a _dissolvent_ of it. But leaving these inquiries to Physicians
or Chymists, to whom it does more properly belong, I shall proceed.

* * * * *

Observ. XIII. _Of the small _Diamants_, or _Sparks_ in _Flints_._

Chancing to break a Flint stone in pieces, I found within it a certain
cavity all crusted over with a very pretty candied substance, some of the
parts of which, upon changing the posture of the Stone, in respect of the
_Incident_ light, exhibited a number of small, but very vivid reflections;
and having made use of my _Microscope_, I could perceive the whole surface
of that cavity to be all beset with a multitude of little _Crystaline_ or
_Adamantine_ bodies, so curiously shap'd, that it afforded a not unpleasing
object.

Having considered those vivid _repercussions_ of light, I found them to be
made partly from the plain external surface of these regularly figured
bodies (which afforded the vivid reflexions) and partly to be made from
within the somewhat _pellucid_ body, that is, from some surface of the
body, opposite to that superficies of it which was next the eye.

And because these bodies were so small, that I could not well come to make
Experiments and Examinations of them, I provided me several small _stiriae_
of Crystals or Diamants, found in great quantities in _Cornwall_ and are
therefore commonly called _Cornish Diamants_: these being very _pellucid_,
and growing in a hollow cavity of a Rock (as I have been several times
informed by those that have obs