428 M. H. Becquerel's Experimental Investigations 



other, gives rise to the very peculiar modification known as 

 ozone. However, I propose to investigate more fully the 

 cause of the anomaly just noticed. 



III. Magnetic Rotations of Gases compared with Carbon Bisul- 

 phide for the Yell oio Rays of Soda. 

 The relation above established between the magnetic rota- 

 tions of the planes of polarization of rays of different colours 

 and the wave-length of the corresponding light, enables us to 

 determine the magnetic rotation relative to the yellow light of 

 soda which corresponds to the rays D in the solar spectrum. 

 In order to effect this determination, use may be made of all 

 the numbers obtained for the different colours, either by means 

 of graphical representation, or by dividing each of them by the 

 inverse ratio of the squares of the wave-lengths. In this way 

 the following results have been obtained for the different gases 

 (oxygen, which has already been considered, is excluded from 

 the following table): — 



Rotations for the Yellow Light D, deduced from Observations 



with Rays of different Colours. 



Atmospheric Air. 



^ i n x -i Numbers T. r Mean 



Colour of the rays. obtained> Mean. deviat ion. 



Red rays 6'73^ 



Yellow rays 0*72 ! rv79n _r 



White „ 0-70 f U lLK} ™ 



Green „ 072J 



Nitrogen. 

 White rays 0-729 



Carbonic Acid. 



White rays 1'37| vm j 



Green „ rdb ) lcJ0 



Nitrous Oxide. 



White rays 1*82) lt7ft , 



Green „ 1-74/ 178 & 



Sulphurous Acid. 



Red rays 3'302) 



Yellow ravs 3-288 V 3-300 a fi 



Green /, 3'306J 



defiant Gas. 



Red rays 3-626} 



Yellow rays 3-621 f 



White „ 3-636 ? 6 625 seo 



Green 9} 3*616 J 



