For placing the Object, I made this contrivance; upon the end of a
small brass Link or Staple HH, I so fastned a round Plate II, that it
might be turn'd round upon its Center K, and going pretty stiff, would
stand fixt in any posture it was set; on the side of this was fixt a
small Pillar P, about three quarters of an inch high, and through the
top of this was thrust a small Iron pin M, whose top just stood over
the Center of the Plate; on this top I fixt a small Object, and by
means of these contrivances I was able to turn it into all kind of
positions, both to my Eye and the Light; for by moving round the small
Plate on its center, could move it one way, and by turning the Pin M, I
could move it another way, and this without stirring the Glass at all,
or at least but very little; the Plate likewise I could move to and fro
to any part of the Pedestal (which in many cases was very convenient)
and fix it also in any Position, by means of a Nut N, which was screw'd
on upon the lower part of the Pillar CC. All the other Contrivances are
obvious enough from the draught, and will need no description.
Now though this were the Instrument I made most use of, yet I have made
several other Tryals with other kinds of Microscopes, which both for
_matter_ and _form_ were very different from common spherical Glasses.
Pages:
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54