on the rates of chronometers . 
375 
Eight-day Box Chronometer A. 
Mean 
Temp. 
Pressure. 
Number 
of days. 
Mean 
daily rate. 
First set of Experiments. 
o 
58 
detached 1 
30 in. 1 
5 
— s".i 
59 
20 in. 
4 
- l ".3 
59 
to in. 
4 
+ l ".7 
59 
l in. 
4 
+ 6". 6 
59 
detached 
29.85 in. 
10 
— 6 ". 3 
Second set of Experiments. 
59 
detached 
29.85 
10 
— GT.s 
57 
25 in. 
2 ,/ .2 
58 
10 in. 
4 
+ 2" 7 
58 
5 in. 
4 
+ 4 ".6 
57 
detached 
30.02 in. 
IO 
— 5". 9 
These remarkable changes having taken place in the daily- 
rate of a chronometer, known under the ordinary circum- 
stances of atmospheric pressure to preserve a steady uni- 
formity of rate, I was induced to employ, in the next place, 
three good pocket chronometers, whose detached rates are 
