192 



From the mean value of A from table II, it would appear that the 

 value does not vary from unity by more than one-tenth of one per cent. 

 An unfavorable combination of errors could affect the single values by 

 three-tenths of one per cent. 





Tube A. 



in Steam. 





Exp. 



'^' meas. 



"^ cor. 



T. abs. 



1 



38.287 



38.325 



370.80 



2 



38.262 



38.299 



370.76 



3 



38.303 



38.339 



371.12 



4 



38.234 



38.271. 



370.49 



5 



38.252 



38.288 



370.67 



6 



38.275 



38.312 



370.87 



7 



38.231 



38.268 



370.84 



8 



38.291 



38.328 



370.91 











Tube B, in Ice Bath. 



'^ meas. 



''- cor. 



T. abs. 



_^0_ 



ki 00 



32.862 



32.867 



272.5 



1.000758 



32.838 



32.842 





1.000485 



32.860 



32.864 





1.000707 



32.846 



32.851 





1.001770 



32.843 



32.848 





1.001180 



32.807 



32.811 



0.998216 



32.863 



32.869 





1.003972 



32.865 



32.869 





1.001020 



mean 



±0. 



1.001013 

 000376 



Table 2. 



Procedure, Series II. For the second series of measurements the pro- 

 cedure was substantially the same as that for the first. Carefully dried 

 and purified nitrogen was introduced into the tubes. The upper tube sur- 

 rounded by cotton and enclosed in the double walled jacket, was allowed to 

 assume the temperature of the room, its thermometer being read through 

 the mica windows. The lower tube, 2.2 cm. in diameter, was immersed in 

 the liquid air bath, the top of the tube being 2 or 3 cm. below the surface. 

 Temperatures of the liquid air were read by means of a constantan-iron 

 thermo-junction and a sensitive millivoltmeter, which was provided with 

 a calibration curve from the Reiehsanstalt. These temperatures were 

 checked by evaporating samples of the liquid air, mixing with hydrogen 

 and exploding by means of an electric spark in a eudiometer tube. From 

 percentages of oxygen thus found temperatures were interpolated from 

 Baly's curves." 



" Phil. Mag. 49, June 1899. 



