Chase.] 



274 



[Feb. 4, 



These combined results indicate a value, for Earth's semi-axis major, of 

 92737100m. ± 25700 ; the probable error being less than Jg of one percent. 

 This gives, for the velocity of light, 299854 ± 83 kilometres. In the 

 American Journal of Science, for January, 1880, pp. 59-64, D. P. Todd dis- 

 cusses Foucault's, Cornu's and Michelson's experimental estimates of the 

 velocity of ligJit. The following table gives his several values, together 

 with Michelson's final estimate (III), and my own : 



Foucault 298000 km. 



Cornu, I 298500 



II 299990 



Michelson, I 300100 



II 299930 



III 299820 



Todd 299920 



Chase 299854 



Stated Meeting, February 4, 1881. 



Present, 9 members. 



Vice-President, Mr. Eli K. Price, in the Chair. 



Letters accepting membership were read from Dr. Chas. 

 Stewart Wurts, 1701 Walnut St., Jan. 24, 1881; Mr. Henry 

 Carvill Lewis, Germantown, Jan. 25, 1881; Capt. E. Y. 

 McCauley, Lima, Delaware Co., Pa., Jan. 26, 1881 ; Mr. 

 Addison May, West Chester, Pa., Jan. 26, 1881 ; and Prof. 

 Joseph Lovering, Cambridge, Mass., Jan. 31, 1881. 



