38 



ATLAS OF ABSORPTION SPECTRA. 



1 02. Victoria Blue 4 R Continued. 

 Hazy-edged absorption in yellow and 



orange. The red is only partially 

 absorbed. Comparatively weak ab- 

 sorption decreases steadily from 

 o.20/i to about 0.335/1. A band com- 

 mences at 0.495/j, and continues to a 

 maximum at 0.53/x. From this point 

 the band shades off gently towards 

 the red. (The apparent increase of 

 absorption at 0.62^ is probably due 

 to the increasing lack of sensitive- 

 ness of the plate.) 



103. Rhodamine B. (B.) Hydrochloride of 



diethyl-m-amido-phenol-phthaleine. 



Fig. 65, pi. 17; No. 504, S. & J. 



Reddish-violet powder. In solution 

 bluish red, violet. 



7.5 g. per liter. 



Angle 42.5'. Depth o to 0.36 mm. 



Two distinct bands, the one in the yel- 

 low-orange and the other in the 

 green-yellow. Eye observations, 

 changes in concentration, and differ- 

 ent makes of films show that the 

 more refrangible band is the more 

 intense. Fluorescent solution. Ab- 

 sorption decreases gradually from 

 o.20/i to an indefinite limit near 0.32U. 

 Strong absorption from 0.494/j. to 

 about 0.59/i. The maxima are at 

 0.524/i and o.557;u. with the inter- 

 vening minimum of absorption at 

 0.54/j.. Transparent beyond the 

 orange band into the red. 



104. Fast Acid Violet B. (M.) Sodium 



salt of diphenyl - m - amido-phenol- 

 phthalein sulphonic acid. 



Fig. 63, pi. 16; No. 506, S. & J. 



Maroon powder. In solution bluish 

 red, pink. 



3-33 g- per liter. 



Angle 27.3'. Depth o to 0.25 mm. 



Absorption band in the green-yellow. 

 This band is comparatively definite 

 on the green side and has a shadowy 

 companion on the red side. General 

 absorption continues well into the 

 orange-red. All strong lines in the 

 ultra-violet are transmitted. The 

 ultra-violet absorption ends about 

 o.33fi. The visible band begins at 

 0.505/4 and has its maximum near 

 0-53/*- The less refrangible limit is 

 indeterminate. The essential differ- 

 ence between the spectrograms for 

 solutions Nos. 104 and 106 is tliat 



104. Fast Acid Violet B Continued. 



for the former the visible band is 

 asymmetric, whereas for the latter 

 it is symmetric. 



105. Fast Acid Violet A 2 R. (M.) Sodium 



salt of di-o-tolyl - m - amido-phenol- 

 phthalein-sulphonic acid. 



Similar to fig. 19, pi. 5 ; No. 507, S. & J. 



Violet-red powder. In solution red, 

 pink. 



4.67 g. per liter. 



Angle 23.4'. Depth o to 0.21 mm. 



Very narrow, definite band in the 

 green. All strong ultra-violet lines 

 are transmitted. The ultra-violet ab- 

 sorption ends about 0.335/1. The 

 visible band begins at 0.495/t, has its 

 maximum at 0.525/i, and ends near 

 0.57/1. The slanting end of the spec- 

 trogram indicates general absorption 

 in the deep yellow. The green band 

 for this solution is of the same type 

 as the corresponding one for No. 

 104, although it is much less asym- 

 metric, and therefore it resembles 

 more closely No. 106. The spectrum 

 of solution No. 105 is best described 

 as a transition form between Nos. 

 104 and 106. Solutions Nos. 104 

 and 105 have the same empirical 

 formulae. 



106. Acid Rosamine A. (A.) Sodium salt 



of di - mesidyl - m - amido - phenol - 

 phthalein-sulphonic acid. 



Fig. 19, pi. 5 ; No. 508, S. & J. 



Light-red powder. In solution red, 

 pink. 



10 g. per liter. 



Angle 29.3'. Depth o to 0.27 mm. 



Single V-shaped band in the green. 

 Weak absorption beginning with ex- 

 tinction at 0.20/1 and fading gradu- 

 ally to transparency at 0.32/1. Ab- 

 sorption band covers the interval 

 from 0.505/1 to 0.565/1 with its max- 

 imum at 0.535/1. Transparent from 

 0.565/* to 0.63/t. 



107. Uranine. (B.) Sodium or potassium 



salt of fluoresceine. 



Figs. 15 and 16, pi. 4; No. 510, S. & J. 



Yellowish-brown powder. In solution 

 reddish yellow, yellow. 



Intense, narrow band in the blue-green 

 with a weaker companion on its more 

 refrangible side. Very strong, yel- 

 lowish-green fluorescence. 



