ANILINE BROWNS.
207
minutes the reaction is complete. The liquid, when cold, is mixed withchloride of sodium, and the geranosine precipitated is colleded on filters.The colour is soluble in water, and especially in alcohol. It is not decolourisedby ammonia. Acids make the shades brighter.
Saffranine.
This is a colouring matter of a bright red rose, resembling carthamine. Itis produced by the adtion of nitrites upon heavy anilines : 2 parts of baranilineare heated for five or six minutes to 8o° to ioo° C., with 1 part of arsenic acidand 1 part of a metallic nitrite, when a coloured mass is obtained which istreated with boiling water. The solution is neutralised with an alkali. Theintensely red liquid is filtered, and precipitated with common salt. The pre-cipitate, filtered and drained, is sold as a paste. Saffranine is also producibleby the adtion of chromic acid.
The shade of specimen is produced by mixing 1 gill of saffranine paste with20 gills of the subjoined thickening :—1 gallon of acetate of alumina standard,1 gallon of water, 2 lbs. of starch. Boil, cool, and add 1 pint of arsenic andglycerine standard.
The “ Acetate of Alumina Standard ” is made with :—1 gallon of boilingwater, 2& lbs. of alum. Dissolve, and add 3 lbs. of white acetate of lead.Dissolve, let settle, and use the clear liquid.
The “ Arsenic and Glycerine Standard ”:—1 gallon glycerine, 4 lbs.arsenious acid. Boil till dissolved, and filter.
After the saffranine colour has been printed on the goods are steamed forthirty minutes.
Phcenicine.
This is another fine red colouring matter, discovered by Willm in 1861, andprepared by boiling an acetic solution of mauveine with binoxide of barium.The ponceau shade is quickly developed. The boiling is then stopped, andthe excess of acetic acid is exadtly neutralised with a standard solution ofcarbonate of soda. Carbonate of baryta is added, the mixture is filtered, andphcenicine remains in the filtrate. It may be thrown down by the addition ofcommon salt.
Phcenicine may be analogous to the geranosine of Luthringer. It maypossibly be identical with the ponceau colour described by Delvaux. Hedissolves 1 part of chromic acid in 18 to 20 parts of water, and adds 1 part ofaniline. After standing for some hours a blackish precipitate is formed, whichis filtered off, while the liquid retains a yellowish-brown colour. The preci-pitate on treatment with boiling water yields a liquid which dyes silk or woolof a reddish-violet. If rendered alkaline with ammonia the violet colour isthrown down, and the red or ponceau remains in solution.
ANILINE BROWNS.
A maroon-brown was patented by Girard and De Laire in 1863 : they take4 parts by weight of anhydrous hydrochlorate of aniline, and 1 part of drymagenta (not an acetate), which is put in as soon as the hydrochlorate melts.When the magenta is perfectly dissolved the heat is raised to 240° C., andmaintained until the colour—which was at first of a reddish violet—suddenlybecomes a maroon. The process lasts one hour or two, and its approaching