u « a.*-
are both moveable, fo that their refpeftive diftances may be eafify
varied. There is alfo a condenfing glafs to the ftage, for in-
creaftngthe denflty of the light, when it is reflected by the mirror
from a candle or lamp. It is furnifhed with two mirrors, one
plane, and the other concave, and may he ufed as a Angle
microfcope.
A B , Fig. 1, Plate IV. reprefents the body o f the microfcope,.
containing a double eye glafs, and a body glafs; it is here fhewn
as fcrewed to the arm C D, from whence it may be occafionally
removed, either for the convenience o f packing, or when the
inftrument is to be ufed as a Angle microfcope.
The eye glaffes and the body glaffes are contained in a tube
which Ats into the exterior tube A B ; by pulling out a little this,
tube, when the microfcope is in ufe* the magnifying power of each
lens is increafed.
The body A B o f the microfcope is fupported by the arm CTX,
this arm is Axed to the main pillar C F, which is fcrewed Armly to
the mahogany pedeAal G H ; there is a drawer to this pedeflal-,
which holds the apparatus.
N I S is the plate or ftage which carries the Aider-holder K L„
this ftage is moved.up or down the pillar C F, by turning _tjhe
milled nut M ; this nut is Axed to a pinion, that works in a
toothed rack cut on one Ade o f the pillar. By means o f this,
pinion, the ftage may be gradually raifed or depreffed,. and the
objeCt adjufted to. the focus of the different lenfes.
I L
K L is the flider-holder, which Ats into a hole that is in the
middle o f the ftage N I S ; it is ufed to conAne and guide either
the motion o f the Aiders which contain the objefts, or the glafs
tubes that are deftgned to conAne fmalt ftfhes, for viewing thecir-
eulation of the blood. The Aiders are to be palled between the
two upper plates, the tubes through the bent plates.
L is a brafs tube, to the- upper part o f which is Axed the condenfing
lens before fpoken o f ; it Ats into the under part o f the
flider-holder N I, and may be fet at different diftances from the
objeCt, according to it’s diftance from the mirror or the candle:
This tube is feen further drawn out in Fig. 2, Plate IV.
O Is the frame which holds the two reflecting mirrors, one of
which is plane, the other concave. Thefe mirrors may be moved
in various directions, in order to refleCt the light properly, by
means o f the pivots on which they move, in the femicircle Q
S R, and the motion o f the femicircle itfelf on the pin S ; the
concave mirror generally anfwers belt m the day-time-; the plane
mirror combines better with the condenftng lens, and a lamp or
candle. At D there is a focket for receiving the pin of the arm
Q, Plate IX. to which the concave fpeculum, for reflefting light
on opake objefts, is Axed.
At S is a hole and flit for receiving either the nippers L , Plate-
IX. or the ftfh-pan I ; when thefe are ufed, the flider-holder muft
be removed.
T , a hole to receive the pin of the convex liens M, Plate IX.
T®