J^he Microfcope explained, xxiii 
P, is a fifh-pan to faften a fmall fifli on, to fee the 
circulation of the blood, its tail being fpread acrofs the 
oblong hole at the fmalleft end ; then by fhoving the but¬ 
ton inwards through a flit made in the ftage, a fmall brafs 
fpring under the ftage will keep it fteady ; for viewing it 
the tail may be brought exadtly under the magnifier, by 
turning the pan on the button, or by fhoving it inwards 
or outwards along the flit in the ftage. 
All tranfparent objedts are well illuminated in this mi¬ 
crofcope, either by candle or fky-light reflected upwards 
from a concave looking-glafs R, placed in a frame upon 
the center cf the pedeftal. While you are viewing the 
objedt through the microfcope, turn this concave upon 
Its horizontal poles a b, and you will foon find out that 
pofition of it wherein it refledts the moft light through 
the hole c upon the objedt. 
Opake objedts when laid upon the plate s, which is on 
one fide black ebony, and on the other a piece of white 
ivory, being laid over the hole c, in the ftage, may be 
illuminated by the light of the fun-fhine or a candle 
tranfmitted through a double convex lens a, which by 
turning on two fcrews, e, d, and the foot of it put into 
the hole f of the ftage. The candle muft be placed in 
a line drawn from the object through the middle of this 
lens at fuch a diftance to be found by trial as will form 
the fmalleft fpot of light upon the object plate. By day- 
light this glafs is of no fervice, 
T, an i,vory cone to fcrew on to a male fcrew under 
the center of the ftage : its ufe is to intercept feme part 
of the oblique rays when the firft and fecond magnifiers 
are ufed. 
V, a glafs tube to put a fmall frog of newt in r to fee 
the circulation of the blood. When the objedt is well 
expanded on the infide of the tube, Hide it over the hole 
c, in the center of the ftage; and bring that part of the 
object you would examine directly under the magnifier. 
c 4 YT X 
