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V. The dying of wool black.

The natural grease of wool, of great advantage to itin the warehouse, as being a sure preservative against themoth, must necessarily be removed, before it is attemptedto be dyed of any kind of colour : the more perfectly itis cleansed, the better it will be disposed to receive thedye.

The liquor commonly used for the fcowering of fleecewool is said to be a mixture of stale urine with twice orthrice its quantity of water. This mixture being madescalding hot, but not boiling, for a boiling heat wouldfelt the wool, or make it run into lumps, so much wool,as the copper will conveniently receive, is dipt in it, andturned from time to time with wooden poles, for a quar-ter of an hour or more: it is then carried in a large basketinto running water, where it is worked by two men,backwards and forwards, one drawing it from under theothers pole, till it ceases to render the water turbid. Thevolatile alcaline fait, produced in urine by putrefaction,unites with the greasy matter into a soapy compound,which,dissolving imperfectly in water, continues to give the tur-bid appearance till it is totally washed out. The woolis said to lose in this process between one fifth and onefourth of its weight.

The wool thus cleansed is dyed blue, then simmeredwith galls, and the black dye finished with logwood andvitriol; or for a finer black, which however is seldomwanted on wool, the above method with verdegris maybe followed. The manner of procedure is in all respectsthe fame with that for dying woollen cloth; and all theobservations, mentioned Under the foregoing articles, areequally applicable here. It is only to be added, that theoperations, which wool has to undergo, render the pre-venting