The Microfcope explained. iii 
turning the large ivory head I; the fcrew at H being firfl 
difcharged, G G Hides dole to the upper part of the 
long bar K L, which laft is fixed at N and N, to the 
toothed wheel NON, this wheel being ftrongly fup- 
ported by four fcroles whofe extremities are connected 
to an horizontal plate n, which gives an horizontal 
motion to the wheel NON, the bar KL, and every 
other part of the microfcope which is conneted thereto, 
the whole being fupported upon the pillar M, by the 
three feet P P P. 
In fig. 3. the variable microfcope is delineated from its 
perpendicular pofition, being that which gave the beft 
reprefentation of its feveral parts. In fig. 1. it is drawn 
inclined, from a view of which there will be no difficulty 
to conceive that on turning the key S, the pinion which 
works in the teeth of the wheel NON will give the bar 
K L, with the microfcope and its appendages, any 
oblique inclination that may be required. 
The objet carrying piece or firage DDD, has a large 
round hole T, in the middle over which w r e place the 
objedts for obfervation, fometimes in an ivory Aider, 
No. 1. fig. 3. or upon a Aip of glafs, No. 2. or they 
may be put upon one of the round glafles No. 2. fig. 3. 
which are of various colours and fitted to the hole at T. 
The concave mirror Q_Q_ turns vertically on the ex¬ 
tremities of the femicircle g, and horizontally in the cy¬ 
linder h, by which means it may be turned into any 
diretion, fo as to reflect the light from a bright cloud 
through the center of the ftage at T, projecting the 
image of the object thro’ the body of the microfcope to 
the eye at E. 
The mirror Q_Q, may be extremely well illuminated 
at night by means of a new apparatus contrived for that 
purpofe ; it is reprefented at fig. 2. and confifts of a pil¬ 
lar A B, that fupports a femicircle C D 5 on the extre¬ 
mities of this, a fhort tube E F, turns upon axes, one 
b 2 of 
