524 



Prof. E. C. C. Baly on 

 Table IV. 



Factors. 



1/X. 



X calc. 



\ obs. (Coblentz). 



19x3'8 



722 



13-85 



13-7 



22x3*8 



83-6 



11% 



11-98 



23x3-8 



87-4 



11-44 



11-43 



25x3-8 



95-0 



1053 



10-4 



27x3-8 



102-6 



9-75 



99 



28x3-8 



106-4 



9-40 



9-3 



30x3-8 



114-0 



8-77 



8-9 



40x3-8 



152-C 



6-58 



6-51 



43x3 8 



163-4 



6-12 



6-1 



45x3-8 



171-0 



5-85 



5-8 



88x3-8 



334-4 



2-99 



2-98 



The agreement shown in this table would certainly justify 

 the conclusion that 3*8 is the principal basis constant of 

 ammonia. We are now able to calculate the wave-lengths 

 of the component lines of the ultra-violet absorption band 

 group of aniline, for the central frequency is known, as are 

 the basis constants; for, as in the case of phenol, the two 

 benzene constants may be used, 3 '7 and 4*0, together with 

 that now found for ammonia, namely 3*8. I have calculated 

 the whole of the wave-lengths of the absorption lines, and a 

 portion is given in Table V. The observed values are published 

 by Purvis* and by Kochj. 



In his paper Purvis gives three series of measurements 

 made at 14°, 30°, and 45°; and the values for the same line 

 differ in some cases by as much as one Angstrom. This 

 cannot be due to any temperature effect, as the differences 

 are not in the same direction with a given temperature 

 change. The variable values must either be due to expe- 

 rimental error or to the fact that there exist more lines than 

 Purvis actually records. While disposed to favour the latter 

 explanation, I have bracketed together the values which 

 would seem from Purvis's paper to refer to the same line. 

 The agreement between observed and calculated values is 

 very good; and it is also to be remarked that with very few 

 exceptions each line on one side of the centre has its 

 counterpart on the other side. 



* Loc. cit. 



t Zeit. iciss. Phot. ix. p. 401 (1910). 



