The MicrofcGpe explained. 
tv 
Table I. Table II. 
Magnifying 
Powers. 
Diameter 
Surface. 
Solidity. 
i 
624.85 
3 S 937 6 
2 4 I 97 ° 3 2 4 
2 
184.36 
32856 
6035504 
3 
69.51 
4716 
328509 
4 
39.16 
1521 
59319 
5 
26.46 
679 
17576 
6 
16.71 
256 
4O96 
i 
203.25 
41209 
8365427 
2 
79.89 
6241 
493 o6 9 
3 
45*^5 
IO25 
46125 
4 
28.35 
784 
21952 
5 
15.92 
22 5 
3375 
6 
I2 *39 
144 
1728 
Revo¬ 
luti¬ 
ons. 
The meafure 
of any num¬ 
ber of revo¬ 
lutions given 
to any extent 
on the llage. 
I 
146 
2 
2 93 
3 
440 
4 
586 
r“ 
D 
733 
6 
880 
7 
1026 
8 
11 73 
9 
1320 
10 
1466 
20 
2 933 
30 
4400 
40 
58 66 
The firft of thefe tables was made from the mean 
diftance of all the magnifiers from the ftage, or in other 
words the mean height of the needle-point from the ob¬ 
ject; but as this is done only to ftiew how to form fuch 
another fett of tables, if more exadtnefs be required, it 
may be neceflary to have three fuch tables, at leaf! one 
for the mean height between the two greateft, one a 
mean between the two middle magnifiers, and a third be¬ 
tween the two (halloweft. 
Thefe tables being once made, their ufe is very eafy; 
tile firft table of the meafures anfwering to the revolu¬ 
tions 
