140 MORRIS LOEB 



Aniline Yellow (hydrochloride), CizHjzNsCl, made by the action of 

 nitrous acid on an excess of aniline. 



Alizarin, Ci 4 H 8 O 4 , made artificially by successive treatments of anthra- 

 cene with chromic acid and fuming sulphuric acid, and melting the product 

 with potassium hydroxide. Among the dyes allied to alizarin are: Alizarin 

 Black, CioH 6 O4.NaHSO 3 ; Alizarin Blue, Ci 7 H 9 NO 4 ; Alizarin Orange, 

 C 14 H 7 NO 6 ; and Alizarin Violet, or Gallein, C 2 oH 10 O 7 . 



Auramin (hydrochloride), CnH^NsOCl, made by the successive action 

 of phosgene gas (carbon oxychloride) and ammonia upon dimethyl-aniline. 



Aurantia (ammonium salt of hexanitro-diphenylamine), C^HsNyO^. 

 NH 4 , made by the action of nitric acid on methyl-diphenylamine. 



Aurin, CigH^Os, made by the action of oxalic and sulphuric acids on 

 phenol. 



Benzaldehyde Green. See Malachite Green below. 



Benzidine Red. See Congo Red below. 



Benzopurpurins, dyes of various red shades. They are chemically al- 

 lied to Congo Red (which see below), and are made by treating salts of 

 toluidine (which is made from nitrotoluene, and is analogous to benzidine) 

 with nitrous acid, and combining the resulting salts with a- and /2-naph- 

 thylamine-sulphonic acids. 



Bismarck Brown. See Aniline Brown above. 



Blackley Blue. See Indulin below. 



Bordeaux. See Ponceaux below. 



Chryso'idin (hydrochloride), C^HisN^l, made by the action of diazo- 

 benzene chloride on metaphenylene-diamine in aqueous solution. 



Congo Red, or Benzidine Red, C 3 2H22N6S2O 6 Na2, made by the action 

 of nitrous acid and then of sodium naphthionate on benzidine hydro- 

 chloride. 



Eosin, C2oH605Br 4 K 2 , or C2oHeO5Br 4 Na2, made by the action of bromine 

 on fluorescem. 



Erythrosin, C 20 H 6 O5l 4 Na 2 , made by the action of iodine on fluorescem. 



Fluoresce'in, C2oHi 2 O5, made by the action of phthalic acid anhydride 

 on resorcin. 



Fwcfo^Rosaniline Hydrochloride, Magenta or Aniline Red, C 2 oH 2 oN 3 Cl, 

 made by the oxidation of toluidine and aniline in the presence of acids. 



Gallem. See Alizarin above. 



Helianthin. See Methyl Orange below. 



Indigo. See text of the article above. 



Indulin, or Blackley Blue, CisHisNs, made by heating aniline salts with 

 amidoazobenzene. 



Magenta. See Fuchsin above. 



Malachite Green, Benzaldehyde Green, or Victoria Green, 3C23H 2 5N 2 C1. 

 2ZnCl 2 + H 2 0, made by the condensation of benzaldehyde with dimethyl- 

 aniline, and the subsequent addition of hydrochloric acid and zinc chloride. 



Martius' Yellow, CioH 5 N 2 Q 5 SNa, made by the action of nitric acid on 

 a-naphthol-monosulphonic acid. 



