2l6

DYEING AND CALICO PRINTING.

bases, yet it does not redden litmus, and dissolves alkaline carbonates withoutexpelling the carbonic acid.

Phenol is extracted from the medium and the heavy coal-tar oils by a some-what tedious process, which we need not here particularise, but which consistsin successive treatment with acid and alkaline liquids. The latter, generallysoda, takes up phenol along with the cresylic and phlorylic acids. (SeeReimann’s “ Handbook of Aniline,” p. 144). Among its most importantderivatives is the rosolic or phenoic acid, or aurine, formed by oxidation,and first obtained by Runge.

Dr. R. Angus Smith prepares rosolic acid by heating in a capsule 2 parts ofcommercial phenol, with 1 of caustic potash dissolved in a little water, and5 of peroxide of manganese. A high temperature is required. The resultingmass is dissolved in water, and the alkaline rosolate is decomposed with asuitable quantity of an acid.

Tschelnitz mixes the heavy tar oils with an excess of hydrate of lime, andleaves the whole in a warm airy place for several months. The red mass thusobtained is powdered and treated with dilute sulphuric acid with the aid ofheat. A dense oily scum rises to the surface, and is colledted and boiled inwater as long as any oily produdts are volatilised. The fixed residue, whencold, is placed on a filter, washed in water, dried, and treated with alcohol,which dissolves rosolic and brunolic acids. This solution, treated with milkof lime, gives a rose-coloured solution of rosolate of lime, whilst the brownbrunolate is chiefly precipitated. Pure rosolic acid is obtained by precipitatingthe rosolate of lime with acetic acid, and combining it again with lime. Thistreatment is repeated several times, traces of brunolic acid being eliminatedon each occasion. It is finally dissolved in alcohol, and on evaporationremains as a hard vitreous body of an orange colour.

Persoz mixes 3 parts of carbolic acid, 2 of oxalic, and 2 of sulphuric. Thecarbolic should boil at the constant temperature of 184° C., and the oxalicshould be perfedlly dry. The whole is heated for some hours to a moderatetemperature. During the readtion there is effervescence, the mass thickens,and takes a brownish red colour. The process is at an end when a drop ofthe mixture, thrown into dilute ammonia, gives an intense red colour. It isthen withdrawn from the fire and poured into cold water, which extradls thegreater part of the sulphuric acid as well as the sulphophenic acid which hasbeen formed. It is then repeatedly washed with boiling water. On drying itbecomes a hard brittle mass, with a green refledlion. Rosolic acid gives avariety of fine red shades, which can be easily modified by the aid of reagents.Its unstable charadler renders the fixation of aurine upon fibres and tissuesa matter of some difficulty. The accompanying specimen of “ AurineOrange ” was obtained as follows :—Mix well 8 ozs. of aurine solution andi gallon of ladlarine thickening. The “ thickening” is prepared with—

7 pints Water at 80° F.

1 pint Ammonia,

2 lbs. Ladtarine.

Stir well until perfedtly dissolved. The colour is printed, and steamed fortwenty minutes.

The salts of rosolic acid with the alkaline earths and with lead are nowvery largely employed in paper staining under the trade-name—very misleading