52 a study of the absorption spectra. 



Chromium Chloride and Aluminium Chloride. 



A spectrogram (Plate 27, A) was made to show the effect of rise in 

 temperature on a mixture of chromium chloride and aluminium chloride 

 in water. The concentration of the former was 0.125 normal, and the 

 latter 2.28 normal. The depth of cell was 9 mm. Exposures of 4 minutes 

 wore made to the Nernst glower and 6 minutes to the spark. The current 

 through the glower was 0.8 ampere and the slit- width 0.20 mm. Starting 

 with the strip nearest the comparison scale the temperatures were 6, 19, 

 36, 51, 66, and 81. 



The most marked effect of the aluminium chloride was the production 

 of a very pronounced unsymmetrical broadening. At 6 the ultra-violet 

 band reached to X 3000. At 81 it had widened to almost X 3300, a greater 

 widening than the same band in a pure chromium chloride aqueous solution. 

 At 6 the blue-violet band extends from X 4100 to X 4600, and the yellow 

 band from X 5800 to X 6200. The red sides of the blue-violet and yellow 

 bands not only widen out enormously towards the red, but the short wave- 

 length edges of these bands move towards the red. This effect is a continu- 

 ous one, but is much greater for the temperature changes from 51 to 66 

 and 66 to 81. At 81 the blue-violet band extends from X 4150 to X 5050, 

 and the yellow band from X 5900 throughout the remainder of the spectrum 

 as far as the film is sensitive. The fine bands in the red do not appear. 



Chromium Chloride and Calcium Chloride. 



A spectrogram (Plate 27 ,B) was made of a mixture of chromium chloride 

 and calcium chloride in aqueous solution, the chromium chloride being of 

 0.125 normal concentration and the calcium chloride of 3.45 normal concen- 

 tration. The length of the solution was 9 mm. The exposures to the 

 Nernst glower were for 5 minutes and to the spark 6 minutes. The current 

 through the glower was 0.8 ampere and the slit-width 0.20 mm. Starting 

 with the strip nearest the comparison scale the temperatures were 6, 19, 

 31, 45, 64, and 80. 



The effect of rise in temperature on this solution of chromium and 

 calcium chlorides is very similar to that on chromium and aluminium 

 chlorides. In this case the widening of the ultra-violet band is greater 

 and practically all of this widening takes place in the change of tempera- 

 ture from 45 to 64 and from 64 to 80. In this case the blue-violet 

 and yellow bands widen unsymmetrically, and here too the short wave- 

 length edge of the yellow band not only does not widen but actually nar- 

 rows with rise in temperature. The blue-violet band widens on both 

 edges, the greater widening, however, being on the red side. 



At 6 the ultra-violet band extends to A 2800, the blue-violet band 

 from X 4000 to X 4400 and the yellow band from X 5600 to X 6100. At 64 

 the ultra-violet band extends to X 3100, the blue-violet band from X 4000 to 

 X 4600, and the yellow band from X 5650 to X 6300. At 80 the ultra-violet 

 band extends to X 3250, the blue-violet band from X 3950 to X 5000 and the 

 yellow band from X 5700 throughout the red end of the spectrum as far as 

 the film is sensitive. 



