COLORING MATTERS. 



27 



39. Mordant Yellow O. (M.) Sodium salt of 



siilphonaphthalene-azo-salicylic acid. 



Similar to fig. 13, pi. 3 ; No. 1 16, S. & J. 



Yellow powder. In solution reddish 

 yellow, yellow. 



10 g. per liter. 



Angle 31.2'. Depth o to 0.29 mm. 



Absorption in the violet only. Similar 

 absorption to that of solution No. 

 129. Strong absorption from o.20/t 

 to 0.28/4. Slight weakening of ab- 

 sorption from 0.28/1 to 0.34/i. Ab- 

 sorption attains a maximum at 0.36/1 

 and then slopes gradually, with a 

 comparatively definite edge, to trans- 

 parency at 0.44/1. From this point 

 to 0.63/1 complete transparency ex- 

 ists. 



40. Dianil Yellow R. (M.) 



Similar to fig. 37, pi. 10; No. 124, 

 S. & J. 



Orange-yellow powder. In solution 

 clear yellow, yellow. 



Saturated. 



Angle 31.2'. Depth o to 0.29 mm. 



Faint absorption in violet. Similar ab- 

 sorption to that of solution No. 81. 

 Absorption is comparatively strong 

 at 0.20/1 and decreases to partial 

 ' transparency near 0.295/*. A toler- 

 ably weak band extends from this 

 region to about 0.435/1. Its maximum 

 is indeterminate. Transparent from 

 0.44/t to 0.63/t. 

 4i.Resorcine Brown. (A.) Sodium salt of 

 xylene - azo - resorcin-azo-benzene-/- 

 sulphonic acid. 



Fig. 38, pi. 10; No. 137, S. & J. 



Brown powder. In solution brown, 

 yellow. 



7.78 g. per liter. 



Angle 23.4'. Depth o to 0.21 mm. 



Strong absorption in the violet and 

 blue. A more concentrated solution 

 exhibited absorption in the green 

 and yellow. A long band or region 

 of absorption extends from 0.35/1 to 

 0.52/1. The maximum is near 0.395/t. 

 There is a slight minimum of absorp- 

 tion at 0.48/1. The presence of a 

 weaker, less refrangible band, in- 

 creasing in intensity at 0.48/*, is more 

 marked as the concentration is in- 

 creased. More concentrated solutions 

 show that the transparency in the 

 ultra - violet rapidly disappears. 



41. Resorcine Brown Continued. 



whereas the bands do not encroach 

 as rapidly on the yellow. Trans- 

 parent from 0.53/1 to 0.63/1. The 

 absorption of the concentrated solu- 

 tions is like that of solution No. yy, 

 fig- 35- 



42. Acid Brown. (D.) Sodium salt of bi- 



sulphobenzene-disazo-a-naphthol. 



Similar to fig. 39, pi. 10; No. 138, 

 S. & J. 



Brown powder. In solution brown, 

 yellow. 



7.5 g. per liter. 



Angle 25.5'. Depth o to 0.21 mm. 



Absorption in violet and blue. Similar 

 absorption to that of solution No. 8. 

 Very weak absorption from o.20/t 

 to 0.29/t. Transparent to continuous 

 background of spark from 0.29/1 to 

 0.33/1. Weak, indefinite absorption 

 band from 0.33/1 to 0.48/1, with max- 

 imum indeterminate. Transparent to 

 yellow, orange, and red. 



43. Ponceau B O, extra. (A.) Sodium salt 



of benzene-azo-benzene-azo - j8- naph- 

 thol-disulphonic acid. 



Similar to fig. 52, pi. 13 ; No. 146, 

 S. & J. 



Light-brown powder. In solution yel- 

 lowish red, pink. 



7 g. per liter. 



Angle 21.5'. Depth o to 0.20 mm. 



Strong absorption in blue and green. 

 Similar absorption to that of solu- 

 tion No. 21. Absorption decreases 

 from o.20/t to 0.295/1, and then in- 

 creases to a maximum near 0.345/1. 

 This band fades to semi-transparency 

 about 0.4/t. The width and general 

 appearance of the region of separa- 

 tion between the ultra-violet bands 

 and the band in the green resembles 

 much more closely the correspond- 

 ing region for solution No. 48 than 

 for solution No. 21. Transparency 

 continues from 0.4/1 to 0.44/1., where a 

 strong, round band begins. The last 

 band ends at 0.565/t. Its maximum is 

 at 0.51/1. Transparent from 0.565/1 

 to 0.63/1. Absorption from this band 

 moves more rapidly towards the 

 ultra-violet than towards the red, 

 with increasing concentration. Same 

 empirical formula as No. 42. 



