RATIO OF SPECIFIC HEATS. 



19 



Hence 



Tims we fiiul 

 whence 



Division mark 25.00 HjSOj, = 6.47 cm., Hg, at 18" C, 

 " 25.00 HjSOi, = 6.45 cm., Hg, at O" C. 

 Initial temperature 7", = 272.4' -f- 14.63 = 287.03, 

 Final temperature T^ =- 272.4 4- 8.00 = 280.40. 

 The barometer height was found to be 75.07 cm. of Hg. 



Initial pressure : />, = 75.97 -|- 6.45 = 82.42 cm.. 

 Final pressure : p, = 75.97 cm., 



log />A 



'og/2 



log/, - log/o- (log T, - log 7\) '■'^°^'' 

 The following tables are to show in what degree observation.s made on different 

 days, but nnder like conditions, agree with each other. 



EFFLUX TIME 5'*'"^' ; JUNE 13, 1893, 2"- P.M. 



The barometric height for the day was 76.01 cm., and the value of « computed for 

 25.00 at the acid manometer becomes 



« = 1. 40 1 9 

 when the pressure comparison cited above is inserted. 



The following table was obtained on the morning of the same da}', the baro- 

 metric height being 76.06 cm. Hg. 



EFFLUX TIME 2^'''^- ; JUNE 13, 1 893, 12"" M. 



The same [)ressure, 25.07, at the acid manouieter was obtained for au efflux 



time of 6 seconds, while the needle of the galvanometei' remained motionless for 



8 seconds. Availing ourselves of the alwve pressure measurement we thus obtain 



;c = 1. 4012. 



■ The reasons for preferring — 272.4" (". to - 273° C. as tlie position of the absolute zero of 

 temperature will be given on page 25. 



