46 



ATLAS OF ABSORPTION SPECTRA. 



146. Thiogene Brown S Continued. 



0.41/^. On both sides of 0.445^ the 

 absorption is at a minimum. A 

 very shadowy band absorbs from 

 0.49/1 to o.545jit. Its maximum is 

 near 0.523/i. The end of the nega- 

 tive slants a good deal more than 

 that of solution No. 47, and thus 

 points to the absorption in the yel- 

 low and orange. 



147. Thiogene Orange R. (M.) 

 Similar to fig. 12, pi. 3. 



Brown powder. In solution reddish 

 brown, yellow. 



5.83 g. per liter (filtered). 



Angle 50.7'. Depth o to 0.46 mm. 



Weak absorption in the violet. The 

 solution has an unpleasant odor. Its 

 absorption is similar to that of solu- 

 tion No. 30. Absorption is complete 

 from o.20;u to o.25/.(, and then de- 

 creases with a long, gentle curve to 

 transparency about 0.44^(1. Trans- 

 parent from o. 445(11 to 0.63^1. 



Miscellaneous Absorbing Media. 



148. Acetone, Ethyl Alcohol, Methyl .A.lco- 



hol. and Water. 



Fig. 87, pi. 22. 



The depth of the cell was 1.41 cm. for 

 each of the liquids studied. Especial 

 care was taken to have the three 

 organic solvents as nearly anhy- 

 drous and as pure as possible. 



The photographic strip nearest to the 

 comparison spectrum gives the ab- 

 sorption of the column of acetone. 

 The next strip in order corresponds 

 to ethyl alcohol. The third strip per- 

 tains to methyl alcohol and the 

 strip nearest to the numbered scale 

 is the photographic record for dis- 

 tilled water. 



Acetone absorbed all radiations be- 

 tween o.20fi and 3282.4 A. U. and 

 the continuous background as far as 

 3302.7 A. U. 



The most refrangible spark line trans- 

 mitted by the ethyl alcohol had the 

 wave-length 2265.1 A. U. This 

 liquid transmitted all the strong 

 ultra-violet lines, but it absorbed the 

 continuous background from 0.20^ 

 to about o.275i,. 



The methyl alcohol transmitted very 

 faintly the strong cadmium line at 

 2313.0, but no other radiation of 



148. Acetone, Ethyl Alcohol, etc. Cont'd. 



wave-length less than 2502.1. The 

 continuous background in the ultra- 

 violet, on the contrary, was trans- 

 mitted somewhat more freely by the 

 methyl than by the ethyl alcohol. 



The distilled water was perfectly trans- 

 parent to all the radiations in the re- 

 gion photgraphed. 



These results show that even ethyl 

 alcohol is not without sufficient ab- 

 sorption in the remote ultra-violet to 

 make it necessary to take this factor 

 into account when columns two or 

 more cm. long are used. 



149. Aesculine. 



Figr- 73' Pl- 19- 



White powder. In solution colorless. 



Saturated. 



Angle 39.0'. Depth o to 0.36 mm. 



No visible absorption. Intense, blue 

 fluorescence. Absorption decreases 

 from 0.20/J. to semi-transparency 

 about 0.261X. Partial transparency 

 from 0.26/1 to 0.273/i. The band 

 with which the fluorescence is prob- 

 ably associated extends from 0.273/1 

 to 0.363/1 with the maximum near 

 0.32/1. Complete transparency from 

 this band to 0.63/1 and beyond. 



150. Aluminium Chloride, Calcium Bromide, 



and Calcium Chloride. 



Fig. 88, pl. 22. 



The depth of the cell was 1.41 cm. for 

 each of the solutions studied. The 

 photographic strip nearest to the 

 comparison spectrum gives the ab- 

 sorption of the calcium bromide so- 

 lution. The next strip in order corre- 

 sponds to the aluminium chloride. 

 The third strip from the compari- 

 son spectrum pertains to the calcium 

 salt. The remaining strip shows the 

 lack of absorption possessed by dis- 

 tilled water. 



The concentrations of the aluminiuin 

 chloride, calcium bromide, and cal- 

 cium chloride solutions were, re- 

 spectively, 2.75, 4.24, and 4.51 

 normal. The unit used here is the 

 gram-molecular normal ; that is, i 

 liter of solution of unit concen- 

 tration would contain I gram 

 molecule of the anhydrous salt. 



The aluminium chloride solution trans- 

 mitted faintly all of the strongest 



