Monthly Microscopican 
Journal, Dec. 1, 1869. J 
Use of various Microscojpes. 
323 
Indeed all over the world, first-class microscopes have resolved 
the fourteenth, or even the fifteenth band of Nobert's test-plates ; but 
should it be found that American microscopes, even with a ^ih. in. 
objective, have resolved perfectly the nineteenth band, the superiority 
of these instruments would be so enormous that it could easily be 
proved in any place and at any time. 
I wrote to Mr. Hartnack to send me a first-class microscope for 
investigations in anatomy and natural history, and added that I 
intended to compare it carefully with the best American instruments. 
I did not fix the price, and left the choice entirely to him. 
He has sent the instrument marked in his catalogue as No. YIII., 
a new small model, only differing from his great model by wanting 
the rack motion of the tube, by having but three eye-pieces, and 
by lacking two objectives of lower power. 
The catalogue states that this new model, Hartnack's patent, 
differs materially in the optical and mechanical construction from 
his old Oberhauser microscope. I confess I have been unable to 
discover any difference, except that the fine moving screw is placed 
near the top of the tube instead of below. The sliding tube to be 
elongated by another tube has a diaphragm, which is also above the 
objective. The diaphragm under the stage may be removed by a 
sliding apparatus or by a sliding tube. The three eye-pieces, as in 
the Oberhauser instruments, have a low power, 2^, 3-J, 5^ nearly. 
The objectives are No. lY. | in.. No. VII. ith in., and No. IX. 
xVth in., fitted for correction for the cover-glasses, and for immer- 
sion. Hartnack calculates the amplification for the first ranges 
from 70 to 480 with the lower eye-piece, and from 140 to 950 
with the strongest. The camera lucida used with a fourth eye- 
piece goes up to 1000 times. The lowest eye-piece has a glass 
micrometer. 
This instrument costs 390 francs, about 104 • 00 dols. in currency, 
and the camera and lens, 50 francs, about 14 '00 dols. 
The catalogue sent with the microscope gives numbers of the 
objectives from 10 to 18, or from to inch. The ^-^ costs 200 
francs (53 dols.), the ^V? francs (134 dols.), and the other 
numbers vary accordingly. 
The two stronger eye-pieces, 5 and 6, cost ten francs each. 
No. 5 magnifies 7|- times. No. 6 is unknown to me. 
My instrument is No. 8066. Nineteen years ago, in March, 
1850, Professor Yrolik received from the same optician No. 1786. 
Since then he has delivered 6280 microscopes, 330 a year, or almost 
one a day. My instrument was received about six months after I 
ordered it. 
The Section may be interested in seeing an old German micro- 
scope, made in Berlin by Scheck, in 1837, and used by me for 
many years. The defining power is even now sufficient, but the 
z 2 
