350 Mr. Ivory on M. de Freycinet's Experiments 



peratures. Captain Franklin has kindly undertaken to make 

 certain experiments for me in the cold regions to which he 

 has gone ; and probably when he returns from his arduous 

 undertaking, he may have some contributions towards the 

 subject. 

 Royal Institution, May 4, ] 826. 



LIV. Short Abstract of M. de Freycinet's Experiments for 

 determining the Length of the Pendulum. By James Ivory, 

 Esq. M.A. F.R.S.* 



QINCE my former communication in the beginning of the 

 ■**-? month, I have been favoured with the perusal of that part 

 of M. de Freycinet's work which treats of his experiments 

 with the pendulum. In order to complete the view of the 

 present state of this subject, I have hastily drawn up the fol- 

 lowing abstract of the principal results obtained by the labours 

 of M. de Freycinet. The facts of the new experiments are 

 contained in the following table : 



Station. 

 Falkland Islands . . 

 Cape of Good Hope 

 Port Jackson .... 



Rio Janeiro 



Isle of France .... 



Rawakf 



Guam;): 



Mowi§ 



Paris 



Latitude. 



Pendulum. 



5V 

 33 

 33 

 22 

 20 

 

 13 

 .20 

 48 



18"S. 

 15 



34 

 13 

 56 

 34 



51 N. 



7 

 14 



Relative lengths 

 1-00022319 

 •99871582 

 •99877424 

 •99783538 

 •99794215 

 •99709575 

 •99759331 

 •99792816 

 1-00002271 



Inches. 

 39-13712 

 39-07817 

 39-08046 

 39*04371 

 39-04769 

 39-01479 

 39-03023 

 39-04737 

 39-12929 



In this table the relative lengths are the pendulums beating 

 seconds reduced to the level of the sea at the several stations, 

 the seconds pendulum at the observatory at Paris being the 

 unit. Taking 29*12929 in. for the length of the seconds pen- 

 dulum at Paris at the level of the sea and at the standard 

 temperature of 62° Fahr. according to the determination of 

 MM. Biot, Mathieu and Bouvard, the other column of the 

 table contains the pendulums of the several stations in English 

 inches at the standard temperature. 



Besides the relative lengths in the foregoing table, which 

 are those definitely obtained, p. 26 of M. de Freycinet's book, 

 there is another set given in the equations of condition at 



* Communicated by the Author. 

 \ One of the Ladroncs. 



f Island on the coast of N. Guinea* 

 § One of the Sandwich Islands. 



p. 28. 



