9 ° Capt. Kater on the comparison of 
TABLE III. 
Comparisons of various standards 
Date. 
1820. 
Tempera- 
ture. 
Readings of the micrometer 
at 
The Royal 
Society’s 
standard. 
General 
Roy’s 
scale. 
Sir George 
Shuckburgh’s 
scale. 
Bird’s 
standard 
of 176O. 
Col. Lamb- 
ton’s 
standard. 
June 16 
61,5 
l 9 
23 
43 
43 
66 
— 
6 
*7 
4 «>S 
4 1 »S 
58 
— 
8 
»4 
36 
3 6 
5 ° 
, — 
86 
92 
118 
1 18 
>33 
64,0 
75 
93 
“4 
114 
121 
— 
82 
9 1 
1 1 1 
106 
1 26 
— 
78 
93 
1 12 
ic8 
127 
63>5 
75 
93 
113 
1 10 
«2+ 
17 
61,5 
*5 
24 
44 
40 
59 
— 
7 
17 
39 
36 
53 
— 
1 
14 
35 
3 6 
45 
6 4 o 
59 
70 
94 
94 
1 >5 
(By Dr. Wollaston) 18 
64,5 
30 
39 
64 
64 
76 
(By ditto) 
— 
21 
36 
5 6 
5 6 
66 
Mean of the whole 
- - 
4 °, 1 
5 1 * 1 
72,9 
71,6 
87 
I now returned to the forty inch iron bar and General 
Roy’s scale, anxious to verify my former conclusion by a 
fresh examination. The microscopes being fixed at the pro- 
per distance, comparisons were made, which I shall detail 
before I state the results afforded by the preceding table. 
