ALL worsted and woollen yarns used for the surface of carpets, with the exception of those whereon the colours are printed, as in Tapestry carpets, are dyed; and fast and accurate dyeing is of cardinal importance in carpet manufacture. Practically all worsted yarns, and some woollen yarns, however, are supplied to carpet manufacturers by the spinners in oil or in grease; that is to say, still impregnated with the oil which has been put into them in the process of spinning. The freeing of the yarn from this oil by washing is a necessary preliminary to dyeing, inasmuch as the presence of oil would prevent the dye liquor permeating the wool fibres. Scouring is effected by soap and hot water, generally by machines of one type or another. The yarn in skeins is sometimes thrown upon swifts, which revolve over a vat of suds. The skeins are carried through the liquor and well rinsed by the rotation of the swifts. Another method employed is to pass the skeins, tied together in a long chain, through vats in which they are steeped in the suds, and through rollers which squeeze them more or less dry. Or the skeins may travel along a series of aprons, underneath a shower, between rollers, or through bowls of suds. The precise method adopted is not of great importance provided that the scouring solution has full opportunity to operate upon the wool fibres, so that the yarn is delivered ultimately free of oil and of soap. For this reason, a final bath of pure water is desirable. The solvents principally used are ammonia, alkali, and an alkaline soap of some kind. Cotton-seed oil soap is generally regarded as one of the most suitable. The scoured yarn is now ready for dyeing, and passes, without being fully dried, to the sticks or frames of the hand-vat or dyeing machine. The three main considerations to be kept in view in the dyeing of worsted and woollen yarns for carpets are levelness of colour, accuracy of matching, and fastness of colour to light. The second and third are matters which concern the skill of the head dyer and the quality of the dyestuffs which he employs; the first depends upon the handling of the yarn by the operative in the hand vat or dyeing machine; and the essential factor, apart from the proper temperature of the dye-liquor, is motion.