640 Prof. E. C. C. Baly on 



Hydrogen Chloride. 



X (mean of the two infra-red hands) = 3'474/4 *, whence 



if, =8-63.6 xlO 13 . 



In this case the value of — = 38, and the following formula 

 was Used : v 9 



**~ A= 1OT69 xl0^-> Where 10769 >< 1027 =(3H) 2 - 





Values of 



Ou-iUO 8 . 





X. 



Calculated. 



Observed. 



Differences. 



6708 



44372 



44375 



-3 



6433 



44444 



44444 







5790 



44656 



44656 







5770 



44669 



44666 



+3 



5461 



44803 



44800 



+3 



5209 



44930 



44930 







5086 



45001 



45007 



-6 



4800 



45187 



45187 







The paper by Fraulein von Bahr has only just been 

 published, and the values given above are far better than 

 those calculated with the measurement of the absorption 

 band of hydrogen chloride 3'41 /*, given by Angstrom and 

 Palmaer. The value 3*474 is clearly more accurate, and it is 

 extremely satisfactory to find that the refractivities calculated 

 from it agree more closely with the observed values. It is 

 very possible that a re-determination of the absorption band 

 of chlorine would improve the agreement between the calcu- 

 lated and observed refractivities shown in the ensuing table. 



Chlorine, 

 X (infra-red band) = 4*28/* t, whence i/ y = 0*70094 x 10 u . 



In this case the value of — °-=44, and therefore the following 

 formula was used : v 9 



^- 1= 95 7 l'l 2 |t X X^ Where 95U ' 8 X 102 '=(^) 8 - 



* Eva v. Bahr, Deutsch. phys . Gesell. Verh. xv. p. 1150 (1913). 



t Angstrom and Palmaer, Of vers. K. Vet.-Ak. Handl. 1893, No. 6. 



