84 DYEING AND CALICO PRINTING.

sometimes employed instead of, or in combination with, the urine. Othersubstances, such as soda-ash, phosphate of soda, and salts of ammonia, aresometimes substituted or added to this bath, but the favourite material seemsto be stale human urine. The wool, after being drained, is washed in coldwater. In the smaller mills this is performed by stirring up the wool in atank of water with a strong pole, the water being let off through a “ clow”or shuttle, furnished with a grating, at the bottom of the vat, which is againfilled with cold water, the water being renewed several times in succession.In late years a machine known as Petrie’s wool-washing machine has beenintroduced. The wool, steeped as before, is here immersed in water containedin long tanks, and is made to pass forwards, being at the same time openedout by an ingenious arrangement of rakes worked by machinery. Theprinciple in this case is to introduce the wool to liquid which is alreadyfouled by having passed over a first portion, and so gradually to bring it intocontadt with clean water at the other end. Three or four of these vessels areplaced in series, and the wool transferred from one to the other by endlessbands of wire gauze. The wool is put into a tank, from which the wastewater flows away, and issues from the tank to which the clean water is sup-plied. The use of this machine offers an opportunity of economising water,which is of great advantage when the supply is limited. This * scour’ waterruns, in either case, from the vats to the nearest outfall. There is nothing init that is considered worth saving, and we have not heard of its ever havingbeen turned to account or treated in any way. If the wool is not to be dyed,or is to be removed from the premises for that purpose, or if it is to be wovenbefore being dyed, it is dried in hot chambers of various constructions.”

The following analysis of raw merino wool, by M. Chevreul, exhibits the

composition after drying at ioo°. In 100 parts by weight—

Earthy matter deposited by washing the wool in water .. .. 26*06Suint, a peculiar saponified grease, soluble in cold water .. 32*74

Neutral fats .. .. .. 8*57

Earthy matters obtained after the fatty substances were elimi-nated ... .. 1*40

Textile fibre .31*23

Faist gives the following analysis of various wools :—

Hohenheim Wool Hohenheim Hungarian Wool(raw). (washed and dried), (washed and dried).

X- ■ A “ S

Mineral matter .. .. 6-3 16*8 0*94 I'o

Suint and fatty matter 44-3 447 2i - oo 27*0

Pure wool.38*0 28*5 72*00 64*8

Moisture.11*4 7*0 6*o6 7 - 2

100*0 100*0 IOO'OO 100*00

Eisner has found that the loss of weight in wool, treated for the eliminationof the suint with bisulphide of carbon, varies from 15 to 70 per cent withwashed merino wool, 50 to 80 per cent with unwashed wool, and with long orcarded wool 18 per cent.

Suint contains oxalate of lime, chloride of potassium, silica, valerianic acid,two potash salts containing peculiar fatty acids and some fats none of which