3*4

DYEING AND CALICO PRINTING.

chlorites. On the other hand, the colouring matter itself is certainly nota&ed upon in this way, since it is possible to extradt pure alizarin from clothsdyed purple, lilac, and brown, and cleared. When pincoflin is used as adye material the purples produced require no clearing at all, and the ex-planation may be, that either the stronger heat applied has had the effedt ofdestroying the foreign matters which, while becoming fixed to the mordant,affedt the purity of the colours, or this overheating neutralises the reducingeffedt of the organic substances, and as a consequence the peroxide of ironof the mordant does not undergo a partial reduction, and therefore the appli-cation of chlorine is needless. Instead of the nitro-muriate of tin, whichwould injuriously affect the purples, browns, and blacks, sulphuric or oxalicacid is applied, but their use should be avoided wherever possible, since evenwithout these the clearing process affedts the browns and blacks.

For purples, lilacs, browns, and blacks alone the ingredients and quantitiesare as follows :—Cloth, 900 metres; water, 800 litres ; solution of chloride oflime (sp. gr. 1*060); temperature, from 50° to 100 8 ; time, quarter of an hour.Washing in machine with cold water and next the first soap bath:—For900 metres of cloth—Water, 1200 litres; soap, 4*5 kilos.; temperature, 88°;after the first half hour another 1*5 kilos, of soap are added, and the operationcontinued for a further quarter of an hour. Again a washing in the machine,followed by second chlorine bath of the same composition as the first, butthe temperature from 50° to 63° ; time, twenty minutes. Again a washing inthe machine with cold water. Second soaping, for goo metres of cloth:—1200 litres of water and 2 kilos, of soap; temperature, g4°; time, twentyminutes. Again a washing, followed by a bath of bleaching potassa liquor*composed of—Water, 1200 litres; carbonate of soda, 4 kilos.; potassableaching liquor, 10 litres; for 900 metres of cloth at a temperature of 56°,and to last for twenty minutes; this treatment is followed by washing in coldwater in the machine and next drying. No acids are employed, the operationsbeing performed with the aid of soap and the hypochlorite.

When red, brown, and black are printed on the same cloth the clearing opera-tions are conducted as follows:—First, a bleaching bath composed of 800 litres ofwater and 4 litres of bleaching-powder solution at ro6o sp. gr. for 300 metresof cloth ; temperature, from 31 0 to 44 0 ; time, fifteen minutes. Second, washingin the machine, followed by the first soap bath, composed, for 900 metres of cloth,of—Water, 1200 litres ; soap, 4 kilos. ; temperature, from 44° to 56°; time, threequarters of an hour. Again a washing in cold water, and next, if the black isstill deep enough coloured, a bath of nitro-muriate of tin, but if the black willnot stand this a bleaching bath is applied made up, for 300 metres of goods,of 800 litres of water and 4 litres of bleaching-powder solution at 1*060 sp. gr.;temperature, 44 0 ; time, twenty minutes. After this again a washing in coldwater, and next the second soap bath, consisting of—Water, 1200 litres; soap,3 kilos., for goo metres of cloth, to be kept at a temperature of 94 0 for fullythree quarters of an hour. Another washing in cold water is followed up bya third soap bath made up of—Water, 1200 litres; soap, 2*5 kilos., for900 metres of cloth ; temperature, 94 0 ; time, again three quarters of an hour.Again washing in cold water, followed by the third bleaching-powder bath,

* A liquid somewhat akin to the well-known Ban de Javelle (hypochlorite of soda), but con-taining potassa instead. Magnesia will be found preferable.