COLORING MATTERS. 



25 



27. Tropxnline OOO No. 2. Sodium salt of 



/>-sulphobenzeiie-azo-/3-naphthol. 



No. 86, S. & J. 



Bright, orange powder. In solution 

 deep red, salmon pink. 



14 g. per liter. 



Angle 21.3'. Depth o to 0.18 mm. 



Msible absorption and spectrogram 

 identical with No. 26. Similar ab- 

 sorption to that of solution No. 15. 

 Nos. 26 and 27 have the same em- 

 pirical formulae, but differ by a and /? 

 in the naphthol. 



28. Methyl Orange III. (P.) Sodium salt 



of' /-sulphobenzene-azo - dimethylani- 



line. 

 Fig. 41, pi. 11; No. 87, S. & J. 

 Ocher-yellow powder. In solution red, 



yellow. 

 Saturated (heated). 

 Angle 27.3'. Depth o to 0.25 mm. 

 Absorption in blue and green. A strong 



band extends from 0.36/i to 0.525^1. 



This band is very round with its 



maximum at 0.44/x. Transparent 



from 0.525/^ to 0.63/u.. 



29. Tropc-eoHne 00. (C.) Sodium salt of 



^-sulphobenzene-azo - diphenylamine. 

 Similar to fig. 40, pi. 10 ; No. 88, S. & J. 

 Yellow powder. In solution yellowish 



red, yellow. 

 6 g. per liter (heated and filtered). 

 Angle 25.5'. Depth o to 0.21 mm. 

 Delicate absorption in violet and blue. 

 Similar absorption to that of solu- 

 tion No. 32. The extreme ultra- 

 violet absorption is weak because the 

 lines near 0.23/^ show on all three 

 photographic strips. From 0.385^ to 

 0.47/i a weak absorption band obtains 

 with its maximum at 0.43/x. The 

 substance is very transparent to yel- 

 low and red. Nos. 29 and 32 have 

 the same empirical formulae. No. 29 

 is the para-compound and No. 32 is 

 the meta-. No. 29 shows weaker 

 absorption than No. 32. 

 30. Curcumeine. (A.) Mixture of nitrated 

 diphenylamine yellow with nitrodi- 

 phenylamine. 

 Fig. 12, pi. 3; No. 91, S. & J. 

 Ocher-yellow powder. In solution red, 



yellow. 

 Saturated (heated). 

 Angle 27.3'. Depth o to 0.25 mm. 



30. Curcumeine Continued. 



Absorption in violet, blue, and blue- 

 green. Absorption complete at o.20/t, 

 decreasing very gradually with com- 

 paratively definite contour to o.455/t. 

 Transparent from 0.455/x to 0.63^*. 

 31.AZO Acid Yellow. (A.) Azo Yellow, 

 concentrated. (M.) Mixture of 

 nitrated diphenylamine yellow with 

 nitro-diphenylamine. 

 Similar to fig. 12, pi. 3 ; No. 92, S. & J. 

 Ocher-yellow powder. In solution 



brownish yellow, yellow. 

 Saturated (heated). 

 Angle 27.3'. Depth o to 0.25 mm. 

 Strong absorption of violet, blue, and 

 blue-green. Similar absorption to 

 that of solution No. 30. Absorption 

 is nearly complete and uniform from 

 0.20/J. to about 0.39/i. Then the ab- 

 sorption decreases in a gently slop- 

 ing curve to about 0.505/*. Trans- 

 parent to yellow and red. Nos. 30 

 and 31 are mixtures of the same con- 

 stituents and have very similar re- 

 gions of absorption. 

 32. Metanil Yellow. (A.) Sodium salt of 

 w - sulphobenzenc-azo-diphenylamine. 

 Fig. 40, pi. 10; No. 95, S. & J. 

 Brownish-yellow powder. In solution 



yellowish red, yellow. 

 4.29 g. per liter (filtered), 

 ^ngle 23.4'. Depth o to 0.21 mm. 

 Absorption in violet and blue. A band 

 with very indefinite boundary ex- 

 tends from about 0.36/x to 0.47/u.. The 

 maximum is near 0.41JU,. Transparent 

 to yellow and red. A very concen- 

 trated solution shows complete ab- 

 sorption from 0.20/A to 0.5 ijn with a 

 semi-transparent spot at 0.34^'' and 

 maximum absorption at 0.40/i. Ab- 

 sorption ceases abruptly at 0.535/x. 

 33. Naphthylamine Brown. Sodium salt of 

 p - sulphonaphthalene-azo-a-naphthol. 

 Similar to fig. 11, pi. 3 ; No. loi, S. & J. 

 Brown powder. In solution reddish 



brown, almost colorless. 

 I I.I I g. per liter (heated and filtered). 

 Angle"30.o'. Depth o to 0.45 mm. 

 Very weak, general, indefinite absorp- 

 tion for all visible colors of shorter 

 wave-lengtlis than the yellow. Sim- 

 ilar absorption to that of solution 

 No. 47. Absorption was nearly com- 

 plete from 0.20/X to o.274;n. From 



