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DYEING AND CALICO PRINTING.

In printing, Sevez recommends the following process:—

Solution of gum. I litre.

Paste green.250 grms.

Bisulphite of soda . .. 150 „

The mixture is heated in the water-bath to dissolve the salt, and then allowedto stand for three or four days. At the end of this time it is used for printing.The colour will bear steaming, but the'result is less satisfactory upon calicothan upon silk and worsted.

Rosanaphthylamine, or Naphthylamine Red.

To prepare this beautiful colour, introduce into a glass flask, capable ofholding 10 litres,—

3 kilos, of azonaphthyldiamine, in powder;

3 ,, naphthylamine, in powder;

2J ,, crystalline acetic acid.

The flask is now heated in the sand-bath until the mixture is completely dis-solved, but care is taken to keep the temperature between 160° and 180 0 C.The red colouring matter is developed by degrees, and at the same timeammonia is given off. The operator must watch lest the colour should passon into a violet, and stop the operation as soon as the slightest violet colourationappears. At this instant 150 or 200 grms. of crystallisable acetic acid areadded ; the flask is removed from the sand-bath, and the contents are pouredout upon plates of sheet- or cast-iron. The crude matter thus obtained con-tains, besides rosanaphthylamine, acetate of naphthylamine, violet colours, andother secondary produdts. To purify the rosanaphthylamine, 10 kilos, of thecrude matter are treated with 500 litres of water, acidulated with hydrochloricacid. When the solution is complete, and the liquid saturated, it is carefullyfiltered through woollen cloth. The filtrate is exadtly neutralised with carbonateof soda, and mixed with common salt in excess. Hydrochlorate of rosa-naphthylamine is thrown down in a crystallised state. The crystals arepurified by two or three successive solutions in acidulated water and precipi-tations with common salt, and are then sufficiently pure for dyeing.

The colour produces bright rose shades, with a peculiar refledtion whichrenders it valuable for dyeing silks and velvets.

Geranosine.

This beautiful ponceau red, first prepared by Luthringer, is a produdt of theoxidation of rosaniline, and is possibly one of the stages of transition fromrosaniline to rosolic acid.

For its preparation 1 kilo, of any salt of rosaniline is dissolved in 1000 litresof boiling water, and the solution is allowed to cool down to 45° C.

On the other hand, 4i kilos, of the nitrite of barium or calcium, or of per-oxide of barium or calcium, are dissolved in 33 litres of cold water. Thetwo liquids are then mixed, and 10 kilos, of the strongest sulphuric acid areadded. The solution becomes at once a lemon-yellow, and after a fewmoments it is quite colourless. The sulphate of baryta precipitated is filteredoff, and the temperature of the mixture is progressively raised to 100°. Bydegrees the liquid begins to assume an intense red, and after boiling for two