RATIO OF SPECIFIC HEATS. 



17 



the tempenitiires read ort' on the mercury thermometers. Throughout this teui- 

 peratui'e measurement the bahiucing I'esistance W^ iusei'ted at Z was 



70 + lO + 2* + I + .2 + .2* + a + .5 -+- 2, 



of which 2 ohms were inserted before opening the receiver; hence W^ — TFg = 

 2 olims. 



The following results were therefore found on July 12, 1893, 12'®'=- being the 

 period of efflux : 



EFFLUX TIME la^^"^' ; JUNE 12, 1893. 



These data show that 25.23 cm. is the correct value at the pressure manometer, 

 since 25.20 cm. is obviously low and 25.25 cm. too high. 



The data found on the same day for the smallest efflux time of 2 seconds are 

 similarly detailed as follows : 



EFFLUX TIME 2^^'^'^ ; JUNE 12, 1893. 



To accord with this table, 25.00 must be considered as the pressure value 

 most nearly connect ; and indeed the galvanometer needle during this observation 

 remained absolutely at rest for several seconds after expansion. The pressures 

 corresponding to 12^^°- and to 2^^'' of efflux time, differed on that date only by .23 

 cm. of sulphuric acid or by .023 cm. of mercui'y. True, the expansion can no longer 

 be considered adiabatic when the efflux time is as large as 12 seconds, and yet this 

 large variation of the experiment does not change the h value sought, by more 

 ' All the temperatures given are corrected values. 



