THE MICROSCOPE. 
4% 
Achromatic Object-glasses for the Microscope . 
Focal 
length. 
Linear Magnifying 
1 
Power nearly.* 
With Eye-pieces. 
No.l.jNo. 2 . jNo. 3 . 
Angle of 
aperture 
about 
~ 
Price. 
Lieoer- 
kuhn 
addi¬ 
tional. | 
Draw-tube closed 
20 
I 
45 | 
80 
£ 
s. 
d. 
s. 
ij inch 
Add for each inch 
, 
13 degs. 
3 
0 
0 
15 
' 
of tube drawn out 
4 
6 
8 
Tube closed . . 
6 o 
i °5 
180! 
| inch 
Add for each inch 
27 degs. 
3 
3 
0 
II 
of tube . 
7 
12 
20 
Tube closed . 
i 120 
210 
35 ° 
To in cb 
Add for each inch 
55 degs. 
5 
5 
0 
10 
of tube . 
12 
20 
35 
Ditto 
Ditto . . . 
do. 
do. 
do. 
65 degs. 
6 
6 
0 
10 
Ditto 
Ditto . 
do. 
do. 
do. 
75 degs. 
7 
7 
0 
10 
Tube closed . 
240 
430 
720 
i 
1 
i inch 
Add for each inch 
| 85 degs. 
6 
6 
0 
of tube . 
30 
45 
80 
j 
Ditto 
Ditto . . . 
do. 
do. 
do. 
100 degs. 
7 
7 
0 
1 
Tube closed . 
450 
1 7 6 ° 
1300 
g inch 
Add for each inch 
1 
jioo degs. 
8 
8 
0 
of tube . . 
40 
. 
60 
“5 
; 
Ditto 
Ditto . . 
do. 
1 do. 
1 
do. 
120 degs. 
1 
10 
10 
0 
* With the § inch object-glass and the erecting-glasses, employing eye-pieces 
Nos. 1 and 2, the magnifying power will range from 5 to 150 . 
Among the accessories of the microscope due to Messrs. Smith 
and Beck, we must not omit to mention the microscope-table, 
contrived to facilitate the observations of several persons directed 
to the same object with the same microscope. Every one who 
lias used this instrument is aware how fatiguing it is to several 
persons to succeed one another in observing with the same instru¬ 
ment. They are obliged constantly to shift their position, and 
consequently to make their observation standing. The micro¬ 
scope-table, if it do not entirely remove this inconvenience, 
greatly diminishes it. It is a circular table, firmly supported on a 
pillar and claw, capable of being turned with a smooth motion 
round its centre in its own plane. The observers sitting round 
it, the microscope is moved successively to the position occupied 
by each of them by merely turning the table. The best sort of 
84 
