H9 
the length of the pendulum at Madras. 
mined to take a second series ; having made what I consi- 
dered some improvement in detaching the clock and appa- 
ratus from the floor of the building. In this series, besides 
comparisons for the rate of the clock used in the experiments, 
with the transit clock at the time of making the experiments, 
transits of stars were taken with this clock for the purpose. 
The result of this series, however, seems to prove, that every 
necessary precaution had been used in the first, the difference 
of the two being only 0,06 of a vibration in 24 hours.* 
The following are the Observations of the Second Series. 
OBSERVATIONS. 
SECOND SERIES. 
April 18th A. M. Barometer /3°'° l8 
Rate of Clock + o", 9 7 1 i3°f*9 
Hygrometer 12°,6 dry.j Mean - 30,02 5 
Temp. 
Time of coin- 
cidence. 
Arc 
of vibra- 
tion. 
Mean 
Arc. 
Interval 
in 
seconds. 
Number 
of vibra- 
tions. 
Observed 
vibrations 
in 24 hours. 
Correc- 
tion for 
Arc. 
For 
tempe- 
rature. 
Vibrations, 
in 24 hours. 
h. m. s 
O 
O 
/I 
+ 
+ 
82 7 
18 14 21,75 
1.275 
1,122 
71 1,12 
709,12 
86157,00 
2,447 
5,402 
86164,849 
26 12,87 
I. 17 
1,125 
7 12 , 63 
7 IO , 6 3 
86157,52 
2,074 
5469 
86165,063 
83 
38 5’5° 
I, 08 
!.°35 
713, 0 
7M. O 
86157,64 
>,755 
5,550 
86164,045 
49 58.50 
O, 99 
o.953 
713,62 
71 1,62 
86157,86 
1,488 
5, 6 43 
86164,691 
8345 
19 I 52,12 
0,915 
86164,887 
83,05 
Mean 
Rate of the Clock 
+ 0,970 
86165,857 
* By rejecting the 4 in each series, which differs most from the mean, we obtain a mean 
0,03 of a vibration less than that from which the conclusions have been drawn. 
