32 



ATLAS OF ABSORPTION SPECTRA. 



66. Diamine Red E Continued. 



6.36 g-. per liter (warmed and filtered). 



Angle 25.4'. Depth o to 0.23 mm. 



Same visible absorption as No. 64. 

 Similar absorption to that of solution 

 No. 69. Nos. 64 and 66 have the 

 same empirical formulse, but differ- 

 ent chemical constitutions. 



67. Brilliant Congo R. (A). Sodium salt 



of ditolyl-disazo - p - naphthylamine- 

 monosulphonic - j8-naphthylamine-di- 

 sulphonic acid. 



Similar to fig. 26, pi. 7 ; No. 281, S. & J. 



Brown powder. In solution, yellowish 

 red, yellowish red. 



8 g. per liter. 



Angle 31.2'. Depth o to 0.29 mm. 



Hazy-edged band in blue and green. 

 Similar absorption to that of solution 

 No. 69. A pair of unresolved bands 

 extends from 0.42/* to 0.56^, with 

 their chief maximum at 0.515/*. The 

 less refrangible band is the more in- 

 tense. Transparent from 0.555/i to 

 0.63/1. 



68. Diamine Red 3 B. (A.) Sodium salt 



of ditolyl-disazo-bi-j8-naphthylamine- 

 8-sulphonic acid. 



Fig. 61, pi. 16; No. 282, S. & J. 



Reddish-brown powder. In solution 

 reddish brown, brown. 



7 g. per liter (heated and filtered). 



Angle 50.7'. Depth 0.64 mm. to i.io 

 mm. 



Hazy-edged absorption in the blue- 

 green and green A pair of unre- 

 solved bands absorbs from about 

 o.435/t to 0.545/u,. Their maximum 

 is near 0.515/1. The more refrangible 

 band is weaker and more indefinite 

 than its companion. Transparent 

 from 0.545/1 to 0.63U. 



69. Brilliant Purpnrine R. (A.) Sodium 



salt of ditolyl-disazo-naphthionic-;8- 

 naphthylamine-disulphonic acid. 



Fig. 26, pi. 7; No. 283, S. & J. 



Red powder. In .solution red, pink. 



8.75 g. per liter. 



Angle 25.4'. Depth o to 0.23 mm. 



Same visible and photographic absorp- 

 tion as No. 67. Nos. 6y and 69 have 

 the same empirical formulae, but dif- 

 ferent chemical constitutions. Ab- 

 sorption gradually decreases from 

 o.20/t to partial transparency at 

 0.388/i. This minimum of absorption 

 extends to 0.411/1. A pair of unre- 



69. Brilliant Purpurine R Continued. 



solved bands absorbs all radiations 

 between 0.41 i/t and 0.563/1. The less 

 refrangible band is the more intense 

 and has its ma.ximum at 0.515/1. 

 Transparent from 0.563/* to 0.63/1. 



70. Rosazurine B. (B.) Sodium salt of 



ditolyl - disazo - bi - ethyl-;8-naphthyl- 

 amine-sulphonic acid. 



Similar to fig. 26, pi. 7 ; No. 285, S. & J. 



Brown powder. In solution red, pink. 



7 g. per liter (heated). 



Angle 27.3'. Depth o to 0.25 mm. 



Weak absorption in the green, with 

 very hazy, blue boundary. Similar 

 absorption to that of solution No. 69. 

 The precise size and shape of the 

 visible band matches very closely the 

 corresponding band of solution No. 

 45, fig. 25. Ab,sorption from 0.47/*. 

 to 0.55/1, with the maximum near 

 0.515/t. Transparent from 0.55/1 to 

 0.63JU. 



71. Congo Corinth. Sodium salt of ditolyl- 



disazo - naphthionic-a-naphthol-/'-sul- 

 phonic acid. 



Similar to fig. 22, pi. 6; No. 286, S. & J. 



Grayish-black powder. In solution red, 

 pink. 



9.09 g. per liter (very gritty; filtered 

 often). 



Angle 21.5'. Depth o to 0.20 mm. 



General absorption in green, yellow, 

 and orange. Very weak and hazy 

 towards the red. Similar absorption 

 to that of solution No. 74. Weak, 

 general absorption in ultra-violet, 

 permitting all strong lines to pass 

 through the solution. It fades away 

 about 0.35/1. Several plates and films 

 show that absorption begins again 

 about 0.49/t and becomes relatively 

 small at 0.56/1. Weak, general ab- 

 sorption, however, continues to 0.63/1. 

 The maximum of ab.sorption is inde- 

 terminate. Saturated solutions gave 

 the same general results. 



72. Azo Blue. (By.) Sodium salt of ditolyl- 



disazo-bi-a-naphthol-/>-sulphonic acid. 

 Somewhat like fig. 22, pi. 6; No. 287, 



S. & J. 

 Bluish-black powder. In solution deep 



blue, reddish blue. 

 4.29 g. per liter. 



Angle 23.4'. Depth o to 0.21 mm. 

 Hazy-edged absorption in green-yellow, 



yellow, and orange. The red border 



