TABULATED DATA OF ABSORPTION. 



Intermediate Products. 



1. Amidonaphthoklisulphonic Acid IT. (M.) 



Fig. I, pi. I ; pp. 57 and 58, S. & J. 



Grayish-white himps. In solution 

 brownish yellow, colorless. 



Saturated. 



Angle 27.3'. Depth o to 0.25 mm. 



No visible absorption. Intense blue 

 fluorescence. Ultra-violet absorp- 

 tion ends about 0.347/x. 



2. y3-Naphtholdisulphonic Acid G. (M.) 



F'igs. 2 and 5, pi. i ; p. 51, S. & J. 



Pinkish-white powder. In solution 

 colorless. 



Saturated. 



Angle 27.3'. Depth o to 0.25 mm. 



No visible absorption. Intense blue 

 fluorescence. Ab.sorption ends very 

 definitely and follows appro.ximately 

 a straight line from 0.346/i to 0.356/^. 

 Fig. 5 shows absorption exhibited by 

 a solution made by diluting a certain 

 volume of the saturated solution to 

 eight times its original value. 

 3. /'-Nitraniline. (Powder, "extra.") (M.) 



Page 12, S. & J. 



Lemon-yellow powder. In solution yel- 

 low, faint yellow. 



Saturated. 



Angle 37.1'. Depth o to 0.34 mm. 



No visible absorption is produced by 

 a column 6 cm. deep. Entire ultra- 

 violet absorption is weak. A region 

 of slight absorption from 0.20/A to 

 0.255/n is followed by transparency 

 as far aso.34/u. Faint absorption 

 extends from 0.34/A to 0.40/x. From 

 o.40;u. to o.6^fi no absorption is no- 

 ticeable. 



4. o-Nitrobenzaldehyde. (M.) 



Page 61, S. & J. 



White needles. In solution colorless. 



Saturated. 



Angle 31.2'. Depth o to 0.29 mm. 



Extremely weak absorption from 0.20^ 



to 0.24/X. Transparent from 0.24;^ to 



0.6311.. 



5. />-Nitrosodimethylaniline. 



Fig. 3, pi. I ; p. 32, S. & J. 



Dark-green, crystalline powder. In 

 solution brownish yellow, clear yel- 

 low. 



Saturated. 



Angle 23.4'. Depth o to 0.21 mm. 



5. /i-Nitrosodimethylaniline Continued. 



Strong absorption in violet and blue 

 increasing towards the ultra-violet. 

 A remarkably transparent region 

 extends from 0.30/n to 0.375/4. All 

 the strong lines between 0.324/* and 

 0.363/1 are transmitted with almost 

 no decrease in intensity.* A very 

 round band stretches from 0.375/1 to 

 0.448/i with its ma.ximum at 0.432/i. 

 Complete transparency from 0.49/t 

 to 0.63/i. 



6. Resorcine (techn. pure). (M.) 



Fig. 4, pi. I ; p. 45, S. & J. 



White, crystalline lumps. In solution 

 colorless. 



Nearly saturated. 



Angle 29.3'. Depth o to 0.27 mm. 



No visible absorption. Very faint yel- 

 low in a layer a decimeter thick. Ab- 

 sorption ends very abruptly and 

 shows an almost vertical right line 

 determined by 0.287/1 and 0.293/4. 



Coloring Matters. 



7. Naphthol Yellow. (A.) Naphthol Yellow 



S. (M.) Sodium salt of dinitro-a- 

 naphthol-;8-monosulphonic acid. 



Fig. 42, pi. 11; No. 4, S. & J. 



Orange-yellow powder. In solution 

 brownish yellow, pure yellow. 



Saturated (heated). 



Angle 31.2'. Depth o to 0.29 mm. 



Intense band in violet, ultra-violet side 

 invisible. Absorption decreases from 

 0.20/1 towards 0.335/t. Transparent 

 region around 0.335/4. A pair of 

 overlapping bands extends from 

 about 0.345/t to 0.465/4. Their max- 

 imum absorption is at 0.385/4 and 

 their least absorption is at 0.4 1/4. 

 Very transparent from 0.465/1 to be- 

 yond 0.63/t. 



8. Aurantia. Ammonium salt of hexanitro- 



diphenylamine. 



Fi?- 39' pl- 10; No. 6, S. & J. 



Reddish-brown crystals. In solution 

 dull red, yellow. 



10 g. per liter (filtered). 



Angle 42.5'. Depth o to 0.36 mm. 



General absorption in violet. Absorp- 

 tion decreases from o.20/t towards 

 0.28/4. Transparent region from 

 0.28/1 to 0.33/1. Wide band from 

 0.33/4 to 0.49/4 with its ma.ximum 



R. W. Wood. ' On Screens Transparent only to Ultra-Violet Light and their use in Spectrum Photography." 

 Phil. Mag., V. 5, Feb., 1903, pp. 257-263. 



