6 IN T R O D U C T I O N .
P L A T E N O N will give the bar K L, wi t h the Microfcope and all its appendages, any obliquity
or inclination that may be required.
T h e ftage, D D D, with a hole T in the middle, is defigned to place objefts on for
obfervation j thefe being firft fixed in an ivory Aider, N o . i . or upon a Hip o f glafs, K o . 2.
or they may be placed upon one of the round glaiTes which are fitted to the Iiole at T .
T h e concave mirror Q^Q^turns vertically on the extremities of the femicircls g, and
horizontally in the cylinder by whi c h means it may be direfted fo as to refleft the light
thro' the center of the ftage at T , and thence thro' the body of the Microfcope to the
eye at E.
T h e ftage D D hath a conical pin, which fits a hole in the ftider W , in which it may
be turned fideways, fo as to examine any objeft too large for the field of view.
T h e fcrole 6 R has alfo a conical pin fitted to a hole in the Aider V".
B y means of the Aider W the ftage D D may be readily fet to its proper diftance
f r om the magnifier in the button at C , and then by turning the large ivory head I,
the body of rhe Microfcope may be brought to its diftinft focus. If this be not thought
quite fulficient, t ighten the fcrew at H j and then by turning that at X it may be adjufted
to the eye of any obferver wi t h the greateft precifion, and by the help of the Aider V
a proper fpot of light may be readily obtained.
No. 3. is a cyl indrical tube, in which an inner tube i is forced upwards by afpring: its
tife is to receive an ivory Aider N o . i . or a glafs Aider No. 2. the objed being placed in
the center of the hole at m, and the Aider put between the plates ¿> and i. The hollow
at i is to receive a glafs tube for confining a fmall water animal, to fee the circulation
o f the blood.
I f the animakul a in Auids are under confideration, or any very minute infeit, it will
fometimes be neceflary to exclude part o f the l ightwhi c h is ref ieaed from the mirror QJi y
putting the cone N o . 4. upon the bot tom i of N o . 3. it being firft put into the ftage at T .
T h e nippers. No. 5. are for confining any objeft, and are to be placed in one of the
fmall holes near the extremities of the ftage, or in the focket r , at the end of the chain
o f balls. No. 6. as the pointed nippers t, which hold an opaque objeft / -J. The ftage
D D being removed, and one of the fAver fpecula fcrewed to the Microfcope at C , the
Aider W brought near to the Aider V , the ftem x of the pillar belonging to the chain of
balls being put into the hole at W , the balls may be readily managed to give a proper
direftion to the objea: v t, and the obferver's back turned to the window, fo that the
refieition from the mirror of the Acy behind or one fide may fall upon thefilverfpcculum,
and thence be returned upon that part of the objea: t v which ¡s to be examined.
No. 7. is a box containing fpare talcs, to fuppl y the Ivory Aiders.
N o . 8. is a double convex lens, to be ufed as a magnifier in the hand.
L a f t l y , Remove the body A B C , and put the ftage D D into its place in the arm F ;
put the pin of No. 9. into the hole at z , in the top of the bar K L ; place an objeft
upon the ftage 5 and any one of the magnifiers before defcribed may be fcrewed into the
end e o f the Aiding bar e g.
In this ftate of our variable inftrument we have a fingle Microfcope, to whi c h the above
apparatus is applicable: three magnifiers are added, to be ufcd only in this application.
There are l ikewife added to the apparatus, two glafs planes broader than that o f N o . 2.
and two others with hollows ground in them.
A l f o a few flat, round glafles, of different colours, which fit the hole T in the ftage
D D : and a watch glafs, fitted to the fame place, for obferving the animalcula in fluids;
And a fet o f glafs tubes.