98 Mr. Herschel’s account of a series of observations 
July 17th. The loss of observation 1, in columns I. and 
III. was occasioned by the observers mistaking the mi- 
nute. It was however very accurately taken by the second 
observer. 
Rockets. 
App* Time I. 
II. 
- III. 
Mean. 
1 
— 
9 h 32” 20.1 s 
• 
20.1 s 
2 
9 h 42 m 20.0 3 
42 1 9.9 
.. _h _m jp j S 
19.95 
3 
52 20.8 
- - 21.3 
- - 21-3 
21.13 
4 
10 2 21.4 
- - 21.4 
- - 21.4 
21.40 
5 
12 19.8 
- - ! 9-3 
- - I9.2 
19-43 
6 
22 22.9 
- - 22.8 
- - 22.9 
22.87 
7 
32 24.8 
- - 24.8 
- - 24.8 
24.8 
8 
42 25.0 
-- - 25.0 
— - 25.O 
25.0 
9 
. 
- 
:: 10 52 16.0 
— 
10 
11 2 22.5 
- - 22.6 
- - 22.6 
22.57 
Comparison of Chronometer and Clock. 
Chronometer. 
Before g h 2i m 
After 11 11 
Clock. 
i7 h 2 m 3.68 s 
18 52 21.72 
Mean Error and Rate of Sidereal Clock. 
Mean of 7 * s 
I5 h 30“ 
Mean error. 
47.56“ 
Mean rate, 
— 0.06 
Comparison from 16th to 17 th — 1.40. 
Chronometer fast i m 19.00 s 
The ninth rocket exploded the moment it began to ascend: the time noted 
cannot be depended on. 
