391 
on the rates of chronometers. 
found to gain with less pressure, and lose with more ; and the 
tenor of the last experiments confirms the same law. 
The preceding results for the chronometers C and N, may- 
be conveniently arranged in the following tables. 
Effects on the Chronometers C and N, when removed from 
condensed into rarefied air. 
Mean 
Temp. 
Mean 
Pressure. 
Number 
of days. 
Mean daily 
rate of C. 
Mean 
Temp. 
Mean 
Pressure. 
Number 
of days. 
Mean daily 
rate of N. 
50 ° 
36 in. 
5 
+ 0". 7 
47° 
60 in. 
5 
— 8 ".6 
0 
00 
27 in. 
4 
+ 3 " -9 
46° 
1 in. 
1 5 
+ io".7 
Effects on the Chronometers C and N, when removed from 
rarefied into condensed air. 
Mean 
Temp. 
Mean 
Pressure. 
Number 
of days. 
Mean daily 
rate of C. 
Mean 
Temp. 
Mean 
Pressure. 
Number 
of days. 
Mean daily 
rate of N. 
49° 
28 in. 
6 
+ l ".2 
46° 
15 in. 
6 
+ 4".l 
51° 
60 in. 
5 
— 8". 2 
45° 
90 in. 
6 
+ 16". 7 
An opportunity in another experiment was taken, when 
the chronometers C and D had been under the diminished 
pressure of 23 inches for five days, to remove them for a like 
period into the condensing engine, containing air of doub’e 
the mean density of the atmosphere. The result of this 
application was, that the former rate became a decrement of 
