several other Tryals with other kinds of Microscopes, which both for
_matter_ and _form_ were very different from common spherical Glasses. I
have made a _Microscope_ with one piece of Glass, both whose surfaces were
_plains_. I have made another only with a _plano concave_, without any kind
of reflection, divers also by means of _reflection_. I have made others of
_Waters_, _Gums_, _Resins_, _Salts_, _Arsenick_, _Oyls_, and with divers
other _mixtures of watery_ and _oyly Liquors_. And indeed the subject is
capable of a great variety; but I find generally none more useful then that
which is made with _two Glasses_, such as I have already describ'd.

What the things are I observ'd, the following descriptions will manifest;
in brief, they were either _exceeding small Bodies_, or _exceeding small
Pores_, or _exceeding small Motions_, some of each of which the Reader will
find in the following Notes, and such, as I presume, (many of them at
least) will be _new_, and perhaps not less _strange_: Some _specimen_ of
each of which Heads the Reader will find in the subsequent delineations,
and indeed of some more then I was willing there should be; which was
occasioned by my first Intentions to print a much greater number then I
have since found time to compleat. Of such therefore as I had, I selected
only some few of every Head, which for some particulars seem'd most
observable, rejecting the rest as superfluous to the present Design.

What each of the delineated Subjects are, the following descriptions
annext to each will inform, of which I shall here, only once for all, add,
That in divers of them the Gravers have pretty well follow'd my directions
and draughts; and that in making of them, I indeavoured (as far as I was
able) first to discover the true appearance, and next to make a plain
representation of it. This I mention the rather, because of these kind of
Objects there is much more difficulty to discover the true shape, then of
those visible to the naked eye, the same Object seeming quite differing, in