magnifier tliat is then ufed; refleft the fight from the concave
mirror G to the filver fpeculum, from which it will again be reflected
on the objeCt. The glaffes are to be adjufted to their
focal diftance as before direCied.
A L ist of the A pparatus of C uff s. double-constructeo
M ic ro s co p e ,
H a convex lens, to colIeCi the rays o f light from the fun or a
candle, and condenfe them on the objeft.
L a cylindrical tube, open at each fide, with a concave fpeculum
fcrewed to the lower end h.
P the Aider-holder; it eonfifts o f a cylindrical tube, in which
an inner tube is forced upwards by a fpiral fpring, it is uled to>
receive an ivory Aider K, which is to be Aid between the plates h
and i. The cylinder P fits the hole n in the ftage : the hollow-
part at k is defigned to receive a glafs tube N.
R is. a brals cone, to be put under the bottom of the cylinder
P, to intercept oecafionally iome o f the rays o f fight.
S a box containing a concave and a flat glafs, between which a
fmall living infect may be confined; it is to be placed over the
hole n.
T a flat glafs, to lay any occafional objeft upon; there is alfo
a concave one for fluids.
O a
O a long Heel wire, with a fmall pair o f pliers at one end, and
a point at the other, defigned to flick or hold objects; it flips
backwards and forwards in the fliort tube o ; the pin p fits into
the hole o f the ftage.
W a little round ivory box, to hold a fupply o f talc and rings
for the Aiders.
Z a hair brufii, to wipe any duft off the glaffes, or to take up
by the other end a drop o f any liquid.
V a fmall ivory cylinder, that fits on the pointed end o f the
fteel wire O ; it is defigned for opake objects. Light-coloured
ones are to be ftuck upon the dark fide, and vice verfa.
Y a common magnifying glafs, for any occafional purpofe.
M a filh-pan, whereon to fallen a fmall fifli, to view the circulation
o f the blood; the tail is to be fpread acrofs the oblong
hole at the fmall end, and tied faff, by means o f a ribband fixed
thereto ; the knob 1 is to be fhoved through the flit made in the
ftage, that the tail may be brought under the magnifier.
T he D escription and Use of A dams's improved double
and single Microscope, represented Fig. 1, Plate IV .
It is the compound microfcope, which is at prefent in moft
general ufe. The improvements, though few in number, are
effential to the ufe thereof. The field o f view is confiderably
larger than in the former microfcope. The ftage and the minors
L 2 are