diftance, and the light be feen reflefted from the fpeculum
ftrongly upon the objeft, by which means it will appear very
diftinft and clear.
O f Ellis’s Single or A quatic Microscope, Plate VII B
This inftrument takes it’s name from Mr. John Ellis, author of
“ An Effay towards a Natural Hiftory o f Corallines,” and o f the
“ Natural Hiftory o f many curious and uncommon Zoophytes”
This was the inftrument that he made ufe of, and by which he
was enabled to explain many Angularities in the ceconomy and
conftruftion of thefe wonderful productions o f nature. To the
praftical botanift this inftrument is recommended, by the
refpeftable authority o f Mr. Curtis, author o f the Flora Londi-
nenfis, a work which does credit to the author and the nation.
This microfcope is fimple in it’s conftruftion, eafy in its ufe, and
very portable; thefe advantages, as well as fome others which it
alfo has over every other portable microfcope, have accelerated
the fale thereof, and caufed it to be very much adopted.
D escription of the various Parts of the M icroscope.
K, the box which contains the whole apparatus ; it is generally
made o f filh-fkin; on the top of the box there is a female
fcrew, for receiving the fcrew which is at the bottom o f the pillar
A, a pillar o f brafs which is fcrewed on the top o f the box K
D, a brafs pin which fits into the pillar; on the top o f this pin
is a hollow focket to receive the arm which carries the magnifiers; .
the
M i c r o s c o p i c a l E s say s . i l l
the pin is .to he moved up and down, in order to adjuft the lenfes
to their focal Or proper diftance from the objeft.
•N. B. In the reprefentation o f this microfcope, Plate VII. B.
Fig. l, the pin D is delineated as pafllng through a focket at
one fide of the pillar A ; whereas it is ufual at prefent to make it
pafs down a hole bored through the middle o f the pillar.
E, the bar which carries the magnifying lens ; it fits into the
focket X which is at the top of the pillar D. This arm may be
moved backwards and forwards in the focket X, and fideways by
the pin D, fc that the magnifier, which is fcrewed into the ring
at the end E o f this bar, may be eafily made to traverfe over any
part o f the objeft that lays on the ftage or plate B.
E F is a polilhed filver fpeculum, with a magnifying lens,
placed at the center thereof, which is perforated for this purpofe.
The filver fpeculum fcrews into the arm E as at F.
G, another fpeculum, with it’s lens, which is o f a different
magnifying power from the former.
H, the femicircle which fupports the mirror I ; die pin R,
affixed to the femicircle H, pafles through the hole which is towards
the bottom o f the pillar A.
B, the ftage, or the plane, on which the objefts are to be
placed; it fits into the final] dove-tailed arm which is at the
upper end of the pillar D A.
C, a