BAN BECQÜEREL and H. KAMERLINGH ONNES. On the absorptionspectra of the compounds of the rare 

 earths at the temperatures obtainable by liquid hydrogen and their change by the magnetic field. 



PI. V. 



T = 293° abs. 



T= 85' 



T= 20'' 



T= 20= 



T= 14° „ 



T= W 



T^ 14" 



7"= 14° 



r= 14= 



T^ 14= 



Fig. 7. Sulphate of neodyme ; spectra of vibrations in the directions v., /S, ■/ group in the blue, 2d spectrum (Rowland grating^ 



1, 3, 7, 11, 19 « without field 



2, 4, 8, 12, 15 s 

 16, 20 y 

 5 and 6, 9 and 10, 13 and 14 « and ^ normal to field (18000 Gauss) 



» I) 



V ," 



17 and 18, 

 21 and 22 



^ and y „ ., „ 

 a and V „ „ „ 



