[ 251 ] 
XIX. Experiments to ascertain the Correction for V ariations of Temperature, 
within the limits of the natural temperature of the Climate of the South of 
England, of the Invariable Pendulum recently employed by British observers. 
By Captain Edward Sabine of the Royal Artillery, Secretary to the Royal 
Society. 
Read March 25th, 1830. 
Having obtained the rate of the invariable pendulum. No. 12, in the Royal 
Observatory at Greenwich at the temperature of 63°.53 in the month of 
August 1829, as given in the preceding paper, the pendulum was laid aside 
until the cold weather of the winter season had set in, when the observations 
detailed in Table C were made with it, at the mean temperature of 31°. 15 ; 
the results of which are exhibited in the following abstract : 
Greenwich, December 1829, and January 1830: Experiments with 
Pendulum 12. 
Dec. 29 
Therm. 
28.50 . 
Barom. 
. 30.212 27.0 . . 
Vibrations. 
85973.99 . . 
Corrected to SI. 
85972.82 
29 
28.55 . 
. 30.227 
27.0 . . 
85973.84 . . 
85972.70 
30 
29.30 . 
. 30.307 
28.0 . . 
85973.66 . . 
85972.85 
30 
29.65 . 
. 30.311 
28.5 . . 
85973.52 . . 
85972.86 
Jan. 1 
31.35 . 
. 30.497 
30.5 . . 
85972.82 . . 
85972.91 
1 
32.00 . 
. 30.472 
31.0 . . 
85972.33 . . 
85972.70 
2 
31.80 . 
. 30.371 
31.0 . . 
85972.46 . . 
85972.75 
3 
33.85 . 
. 30.285 
33.0 . . 
85971.78 . . 
85972.97 
5 
35.40 . 
. 30.149 
34.5 . . 
85970.94 . . 
85972.81 
30.315 
30 
85972.81 
31.15 . 
-.002 Red B . to 32° 
. +-019 Capillary 
Red n . for 30.33 in. 
of air at 31.15 
j +10.77 
30.332 at 32° 
85983.58 at 31.15 
