brittle.  We see, then, the importance of “scouring” wool for the removal of “yolk,” as it is called, dirt, oil, etc.  If this important operation were omitted, or incompletely carried out, each fibre would be more or less covered or varnished with greasy matter, resisting the absorption and fixing of mordant and dye.  As scouring agents, ammonia, carbonate of ammonia, carbonate of soda completely free from caustic, and potash or soda soaps, especially palm-oil soaps, which need not be made with bleached palm oil, but which must be quite free from free alkali, may be used.  In making these palm-oil soaps it is better to err on the side of a little excess of free oil or fat, but if more than 1 per cent. of free fat be present, lathering qualities are then interfered with.  Oleic acid soaps are excellent, but are rather expensive for wool; they are generally used for silks.  Either as a skin soap or a soap for scouring wools, I should prefer one containing about 1/2 per cent. of free fatty matter, of course perfectly equally distributed, and not due to irregular saponification.  On the average the soap solution for scouring wool may contain about 6-1/2 oz. of soap to the gallon of water.  In order to increase the cleansing powers of the soap solution, some ammonia may be added to it.  However, if soap is used for wool-scouring, one thing must be borne in mind, namely, that the water used must not be hard, for if insoluble lime and magnesia soaps are formed and precipitated on the fibre, the scouring will have removed one evil, but replaced it by another.  The principal scouring material used is one of the various forms of commercial carbonate of soda, either alone or in conjunction with soap.  Whatever be the form or name under which the carbonate of soda is sold, it must be free from hydrate of soda, i.e. caustic soda, or, as it is also termed, “causticity.”  By using this carbonate of soda you may dispense with soap, and so be able, even with a hard or calcareous water, to do your wool-scouring without anything like the ill effects that follow the use of soap and calcareous water.  The carbonate of soda solutions ought not to exceed the specific gravity of 1 deg. to 2 deg.  Twaddell (1-1/2 to 3 oz. avoird. per gallon of water).  The safest plan is to work with as considerable a degree of dilution and as low a temperature as are consistent with fetching the dirt and grease off.  The scouring of loose wool, as we may now readily discern, divides itself into three stages:  1st, the stage in which those “yolk” or “suint” constituents soluble in water, are removed by steeping and washing in water.  This operation is generally carried out by the wool-grower himself, for he desires to sell wool, and not wool plus “yolk” or “suint,” and thus he saves himself considerable cost in transport.  The water used in this process should not be at a higher temperature than 113 deg.  F., and the apparatus ought to be provided with an agitator; 2nd, the cleansing or scouring proper, with a weak alkaline solution; 3rd, the rinsing or final washing in water.