344 Metkcd of giving to Cotton and Linen Thread 



ley ; for, as the alkaline carbonate may contain more or less 

 heterogeneous parts, in that case the ley must be weakened 

 or strengthened by a new portion of alkali, until it absolutely 

 assume a milky appearance by the mixture of oil. When 

 the ley is properly proportioned, thirty-two parts of it must 

 be mixed at first 2;radually and then more rapidly, conti- 

 nually stirring it, with one part of olive oil. This milky 

 mixture will keep a long time; and if it be observed that 

 the oil attempts to float under the form of cream, the mix- 

 ture must be again stirred. The impregnation of the skains 

 should be intrusted to workmen most experienced in this 

 operation, because an exact distribution of the oily parts 

 has a great influence in regard to the equality of the shades. 

 Each workman ought to put as much of the milky mixture 

 into any vessel as will admit of a certain number of skains 

 to be squeezed and t\\ isted in it with facility. This labour 

 must be continued, always taking the same number of skains 

 and the same quantity of milky mixture. The part which 

 has been expressed, each time, must be poured into a vessel 

 apart ; and the quantity of oil which the skains appear to 

 have absorbed must be restored, if the little value of this 

 residuum, in consequence of its containing but a small quan- 

 tity of oil, does not make it be rejected. The impregnation 

 may be effected in the whole mass of the milky mixture ; 

 but in this case it will be necessary to continue to replace 

 the quantity of oil which the skains may have absorbed, as 

 soon as a diminution is observed in the intensity of the 

 milky a]ipearance. Expertness in this process may be easily 

 acquired by practice. After the whole skains have been 

 dried together, they must be impregnated a second time as 

 before without being previously washed; and when they have 

 been dried they may be impregnated, as I have mentioned 

 in my memoir, either once, two or three times, in the al- 

 kaline solution of alumine, pure and without any mixture : 

 by immersing the skains, shades more or less dark will then 

 be obtained according to the number of impregnations. 



To obtain, however, bright and at the same time uniform 

 shades, it will be better to employ three impregnations, pro- 

 perly weakening the alkaline solution. One may then im- 

 pregnate three times successively in this concentrated or 

 weakened solution without previous washing : by these 

 means the manipulations, which are often tedious and 

 troublesome, may be shortened ; but in this case it will be 

 necessary to examine the solution from time to time, to see 

 vhether what the impregnated and dried skains discharge in 

 it do not render it too strong. 



In 



