APPENDIX.

679

23. Carminaphtha.— If chromic acid, or a mixture of chromate of potashand sulphuric acid is allowed to adt upon naphthalin, a fine red colouringmatter is frequently formed, under circumstances not yet fully determined.It is a weak acid, almost insoluble in water, soluble in acetic acid and alcohol.With alkalies it forms orange compounds soluble in water, and it dyessilk and wool an orange or a red-violet without the aid of mordants.

24. Chloroxy-naphthalic Acid.—Naphthalin treated in the cold with thechlorate of potash and hydrochloric acid is transformed into a mixture ofbichloride of naphthalin, bichloride of chloro-naphthalin, and certain secondaryoily produdts, which are eliminated by pressure. The residue is heated in awater-bath and oxidised with nitric acid. It is needful to operate cautiously toavoid the formation of large quantities of phthalic acid, and that the bulkof the chloride of chloro-naphthalin may be converted into bichloratednaphtho-quinon, whilst the bichloride of naphthalin forms phthalic andoxalic acids. These acids are removed by boiling water, and the former issubsequently converted into benzoic acid.

The bichloride of naphtho-quinon, which is insoluble in water, is dissolvedin boiling potash-lye ; the deep-coloured solution is filtered and supersaturatedwith a mineral acid, when impure chloroxy-naphthalic acid is thrown down.This is re-dissolved in soda-lye and exadtly neutralised. To the neutral solutiona little alum is added, which precipitates a brown impurity. The liquid isfiltered afresh and mixed with a mineral acid, when the pure chloroxy-naphthalic acid falls as a yellow crystalline powder.

It is soluble in boiling water, alcohol, ether, and benzine. It dissolveswithout decomposition in concentrated sulphuric acid, from which it isre-precipitated on the addition of water. It dyes wool an intense red withoutthe aid of a mordant. If chloroxy-naphthalic acid in an alkaline solution isreduced by means of tin powder, and the solution is boiled for fifteen ortwenty minutes, a yellow liquid is obtained, which when mixed with ammoniaand left to itself, turns green after some time. If it is neutralised with amineral acid a brown flocculent body is precipitated, which when washed anddried appears as a green powder with a metallic refledtion. It is mono-chlorated trioxy-naphthalin. It dissolves in boiling aniline with a red, and insulphuric acid with a green colour. From the latter solution it is throwndown by water with a violet colour. It dissolves in alcohol with a violetcolour, which turns blue on dilution with water. Mono-chlorated trioxy-naphthalin dyes wool and silk a violet, and maybe fixed upon cotton with theaid of albumen.

25. Ballo’s Violet.—Magenta, in the form of acetate of rosaniline, heatedwith naphthylamin or with bromated naphthalin, gives a fine violet.

26. Naphthoic Blue.—The attempts made by Girard, and by Mylius, ofBasle, to replace benzoic acid with naphthoic acid in the conversion ofmagenta into rosaniline blue, have shown that the latter, which is cheaper,gives a blue at least as bright and beautiful as that produced by means of

benzoic acid.

27.— Aniline Grey (Castelhaz).—

Aniline grey (Gris Castelhaz, p. 210). 1 gallon.

“ Reduction paste,” see below .4 gallons.