28 



ATLAS OF ABSORPTION SPECTRA. 



44. Janus Red B. (M.) Chloride of tri- 



methyl-amido- benzene - azo - in - tol- 

 uene-azo-;8-naphthol. 



Similar to fig. 23, pi. 6 ; No. 149, S. & J. 



Reddish-brown powder. In solution 

 yellowish red, faint yellowish red. 



Saturated. 



Angle 54.6'. Depth o to 0.50 mm. 



Pointed, V-shaped, weak band in the 

 blue-green. Similar absorption to 

 that of solution No. 60. Absorption 

 is strong at oaOfi and decreases 

 gradually and in a poorly defined 

 manner to transparency at 0.375/*. 

 The transparent region continues to 

 0.455/it. An absorption band lies be- 

 tween 0.455/n and o.540ya, with its 

 maximum at 0.5 i/x. Slight general 

 absorption in the yellow and orange, 

 but transparent to the red. 



45. Cloth Red G. (O.) Sodium salt of 



toluene - azo-toluene-azo-/?-naphthol- 

 monosulphonic acid. 



Fig. 25, pi. 7; No. 153, S. & J. 



Reddish-brown powder. In solution 

 red, faint pink. 



8.33 g. per liter (heated and filtered). 



Angle 31.2'. Depth o to 0.29 mm. 



Bands in blue-green and green with 

 hazy edges and weak general ab- 

 sorption in both directions. A band 

 extends from o.445yu. to O-S^/x and ap- 

 pears to be composed of a stronger 

 band with a weaker, more refrangible, 

 unresolved companion. Their maxi- 

 mum of absorption is at 0.515/t. The 

 slant at the end of the negative shows 

 that weak, general absorption is ex- 

 erted in the orange. Transparent to 

 the red. 



46. Cloth Red O. (M.) Sodium salt of 



toluene - azo-toluene-azo-/?-naphthol- 

 disulphonic acid. 



Fig. 21, pi. 6; No. 154, S. & J. 



Dark-brown powder. In solution deep 

 red, very faint red. 



6.36 g. per liter (warmed and filtered). 



Angle 33.2'. Depth o to 0.30 mm. 



Maximum of absorption in blue-green 

 with weak absorption in yellow and 

 orange. Absorption band starts at 

 0.485/x, attains its maximum at 0.52/1, 

 and is dissipated in weak general ab- 

 sorption about 0.555/t. The end of 

 the negative slants appreciably. 

 Transparent to red. 



47. Cloth Red 3 G A. (A.) Sodium salt of 



toluene - azo-toluene-azo-;8-naphthyl- 

 amine-monosulphonic acid. 



Fig. II, pi. 3; No. 155, S. & J. 



Brownish-red powder. In solution red- 

 dish brown, light brown. 



Saturated (heated). 



Angle 1 57'. Depth o to 1.07 mm. 



General absorption in violet, also a 

 maximum of absorption in the blue- 

 green and green. Absorption is about 

 complete at 0.20/1 and increases very 

 gradually, with hazy contour, to 

 semi-transparency at about 0.42/*. 

 Semi-transparency from 0.42/i to 

 0.49/n. Weak band from 0.49/x to 

 0.54/i. Transparent from 0.54/1 to 

 0.63/1. 



48. Ponceau 4 R B. (A.) Sodium salt of 



sulphobenzene - azo - benzene - a.zo-/i- 

 najihthol-monosulphonic acid. 



Fig. 51, pi. 13; No. ifio, .S. & J. 



Reddish-brown powder. In solution 

 yellowish red, pink. 



10 g. per liter (heated). 



Angle 19.5'- Depth o to 0.18 mm. 



Strong absorption in blue-green and 

 green. At 0.455/x the strong band be- 

 gins and extends to 0.565/1, with its 

 maximum about 0.5 i/i. Transparent 

 from 0.565/1 to 0.63/1. 



49. Biebrich Scarlet. (K.) Sodium salt of 



sulphobenzene - azo - sulphobenzene - 

 azo-/i(-naphthol. 



Similar to fig. 51, pi. 13; No. 163, 

 S. & J. 



Reddish-brown powder. In solution 

 red, pink. 



6 g. per liter. 



Angle 19.5'. Depth o to 0.18 mm. 



Absorption band in blue-green and 

 green. Absorption decreases from 

 0.20/1 to about o.32/(,, where a semi- 

 transparent region appears. This is 

 followed by an absorption band with 

 its maximum at 0.355/1. Slight ab- 

 sorption from 0.39/1 to 0.45/t. A defi- 

 nite band starts at 0.45/1, reaches a 

 maximum near 0.51/1, and ends at 

 0.555/x. Transparent from 0.555/1 to 

 0.63/1. A solution of 10 g. per liter 

 showed almost complete absorption 

 from 0.20/1 to 0.36/1. From 0.395/1 to 

 0.445/1 only the first photographic 

 strip received light. The band is very 

 round from 0.445/1 to its end at 



