COLORING MATTERS. 



43 



128. Alizarine Creen R Continued. 

 Dark-green powder. In solution dark 



green, light green. 



20 g. per liter (heated and filtered). 



Angle 31.2'. Depth 0.26 to 0.55 mm. 



General absorption in the violet, 

 orange, and red. The minimum of 

 absorption lies in the green, of 

 course. When the depth was o to 

 0.2Q mm., the ultra-violet absorption 

 ended at about 0.355^1. There is no 

 sharp band in the ultra-violet, but 

 simply one-sided absorption, decreas- 

 ing from o.20/i towards the longer 

 wave-lengths. 



129. Columbia Yellow. (A.) Oxidation 



products of dehydrothiotoluidine-sul- 

 phonic acid or of the latter and 

 primuline together. 



Fig. 13, pi. 3 : No. 663, S. & J. 



Brownish-yellow powder. In solution 

 yellow, light yellow. 



10 g. per liter f warmed). 



Angle 31.2'. Depth o to 0.20 mm. 



Weak-edged absorption in violet. Uni- 

 form absorption from o.20;n to about 

 0.36/1. Then a steady decrease in 

 absorption to 0.45/*. Complete trans- 

 parency from 0.4 q/t to o.63/x. 



130. Ouinoline Blue. (G.) No. 664, S. & J. 

 Glistening, green crystals. In solution 



delicate violet, pink. 



Saturated (heated). 



Angle 0. Depth 134 mm. 



Only the blue and blue-green faintly 

 transmitted. (No photograph was 

 taken for the saturated solution.) 

 When 44 cc. of the saturated solu- 

 tion was diluted to 90 cc. a strong 

 band appeared in the yellow and 

 orange, while the red was freely 

 transmitted. The ultra-violet absorp- 

 tion extends to 0.40/* and fades out 

 about o.42;u.. Weak absorption be- 

 gins at 0.48/1 and increases to opacity 

 near 0.55/1. Complete absorption con- 

 tinues to about 0.607/1. Absorption 

 decreases rapidly from 0.607/x to 

 0.63/4. When 44 cc. of the saturated 

 solution was made up to 112 cc. 

 and a column 15 cm. was used, no 

 definite band could be seen, but 

 only a faint weakening of the 

 orange. The ultra-violet absorp- 

 tion was, however, complete as far 

 as 0.374/1 and vanished near 0.395/1. 



131. Ouinoline Yellow, soluble in water. 

 ~ (A.) Quinoline Yellow O. (M.) 



Sodium salt of the sulphonic acid 

 ( chiefly d i s u 1 p h o n i c acid ) of 

 quinophthalone. 



Fig. 44, pi. II ; No. 667, S. & J. 



Yellow powder. In solution lemon yel- 

 low, faint yellow. 



17.5 g. per liter. 



Angle 27.3'. Depth o to 0.25 mm. 



Strong band in extreme violet. One- 

 sided absorption in ultra-violet ends 

 about 0.33/1. Transparent region 

 from o.33/t to 0.345/4. A band com- 

 mences at o.345/t, has its maximum 

 at 0.40/t, and joins a narrow, com- 

 panion band at 0.438/t. Maximum 

 of little band is about 0.448/1 and 

 complete transparency extends from 

 0.453/1 to 0.63/1. For a 5-strip nega- 

 tive the absorption only advanced 

 to 0.463/t. 



132. Indigo Carmine, dry. Sodium salt of 



indigotine disulphonic acid. 



No. 692, S. & J. 



Deep-violet powder. In solution blue, 

 blue. 



10 g. per liter. 



Angle 23.4'. Depth o to 0.21 mm. 



Transmits green and yellow. Moder- 

 ately intense band in the orange-red, 

 beginning about 0.555/1 and increas- 

 ing beyond 0.63/1. General absorp- 

 tion from 0.20/1 to complete trans- 

 parency at 0.37/1. 



133. Acid Magenta S. (A.) Similar to 



fig. 53, pi. 14. 



Dark-green powder. In solution bluish 

 red, bluish pink. 



10 g. per liter. 



Angle 15.6'. Depth o to 0.14 mm. 



Strong band in the green with abrupt 

 edges. Violet, indigo, orange, and 

 red are transmitted. Similar ab- 

 sorption to that of solution No. 95. 

 Partial transparency in the vicinity 

 of 0.265/t. A comparatively weak, 

 narrow band has its maximum near 

 o.295/t, and absorption ceases about 

 0.325/1. An intense region of ab- 

 sorption begins at 0.46/t, has its max- 

 imum at o.535/t, and ends at 0.58/1. 

 Therefore this region slants more at 

 the violet border than at the orange 

 side. The band is very smooth and 

 round. 



