377 
on the rates of chronometers. 
attempt was next made, to ascertain the effect of a more 
gradual diminution thereof, on the same chronometers. The 
results are recorded in the following table : 
Experiments with Pocket Chronometers, B, C, D. 
Mean 
Temp. 
Pressure. 
Number 
of Days. 
Mean daily 
rate of B. 
Mean daily 
rate ofC. 
Mean daily 
rate of D. 
56° 
detached 
30.01 in. 
6 
+ 5 ".o 
+ l".6 
+ 2".4 
58° 
20 in. 
4 
+ 9" -3 
+ 6". 2 
+ 9”. 3 
58° 
10 in. 
4 
+ 1 8 *. 5 
+ n".o 
+ 17 "- 6 
57° 
detached 
29.76 in. 
4 
+ 6". 6 
+ 2".l 
+ 3".5 
A still more gradual decrease of density was preserved in 
another set of experiments, the results of which are recorded 
in the next table. 
Experiments with Pocket Chronometers, B, C, D. 
Mean 
Temp. 
Pressure. 
Number 
of Days. 
Mean daily 
rate of B. 
Mean daily 
rate of C, 
■ 
Mean daily- 
rate of D. 
57 ° 
detached 
29.76 in. 
4 
+ 6". 6 
+ 2".l 
+ S ".5 
59 ° 
25 in. 
4 r 
+ 10". 4 
+ 3". 6 
+ 5 ". 7 
59 ° 
15 in. 
4 
+ 12". 2 
+ 7".6 
+ 12'. 1 
6 o° 
5 in. 
4 
+ 19". 2 
+ H".4 
+ 2 o' 7 . 6 
6o° 
detached 
29.84 in. 
4 
+ 6". 0 
+ °".e J 
T - 4". 2 
3 C 
MDCCCXXIV. 
