PROCEEDINGS OF THE ACADEMY AND AFFILIATED 



SOCIETIES 



THE PHILOSOPHICAL SOCIETY OF WASHINGTON 



The 752cl meeting was held on February 13, 1915, at the Cosmos 

 Club, President Eichelberger in the chair; 48 persons present. Mr. 

 F. B. LiTTELL presented a paper on The Washington-Paris longitude 

 by radio signals. Transit instruments used were of recent type. The 

 observatory standard Riefler clocks were used and ran so well as to 

 justify interpolation over intervals of several days, thus permitting 

 utilization of all the radio work. The lags of clock signals in passing 

 through relays, which in some cases amounted to one-half second, 

 were measured frequently and resulting corrections were applied. The 

 radio signals from the over-sea station were usually extremely faint 

 and oftentimes unobservable. The errors and personal equations due 

 to the radio work were of the same order of magnitude as those due 

 to the astronomical work. From the work of 39 nights, when radio 

 observations in both directions were secured, the double transmission 

 time, free from the errors of clock corrections, was found to be 

 0!0437 ± 0^0039. The preferred resulting value for longitude is 

 5^^ l?-" 36?66 ± 0?003. This agrees well with the adjusted value for 

 4 cable determinations, viz., 5'^ I?'" 36!69. The paper was discussed 

 by Messrs. Paul, Bowie, Abbot, and Pauling. 



Mr. A. J. LoTKA then spoke on Efficiency as a factor in organic evolu- 

 tion. Using the rate of increase per head, r, of a given species of or- 

 ganisms as an index of its adaptation to existing conditions, the func- 

 tional relationship between r and the efficiency of the organism was 

 investigated by analytical methods, making use of the objective stand- 

 ard of values developed by the speaker previously. This efficiency 

 depends on the errors of observation, operation, and mentation of the 

 type-individual, and on the errors of valuation of the representative 

 individual. An expression was obtained for the partial differential 

 coefficient of r with regard to a suitable parameter capable of serving 

 as an index of the imprecision of the organism in a given activity. 

 A separate expression was obtained for the partial differential coeffi- 

 cient of r with regard to errors of valuation. The paper was discussed 

 by Mr. Abbot with reference to applications to economic questions, 

 and by Mr. Burgess. 



The 753d meeting was held on February 27, 1915, at the Cosmos 

 Club, President Eichelberger in the chair; 54 persons present. 



250 '*' 



