372 The Art of Dyeing. 



to stand for twelve hours. Then the necessary quantity 

 of water should be added. If less water is employed, a 

 thick mass is formed, which mixes and dissolves with diffi- 

 culty in water. 



Chloride of lime is employed for bleaching calico. In 

 order that it maybe employed with sufficient advantage, all 

 the soluble leys and acids of the calico should be removed 

 by water. As chloride of lime acts first upon foreign mat- 

 ter attached to the fibre before it bleaches it, a considerable 

 loss of chloride will be experienced, if the cotton contains 

 weavers' glue. The alternate treatment of linen with 

 chloride of lime and sulphuric acid is injurious, but has no 

 bad effect upon cotton. A more certain method is by the 

 employment of chlorine without the addition of acid; and 

 it is still better when it is united with potash or soda, and 

 when the bleaching solution contains an excess of the same. 

 Such a solution may be formed in the following manner 

 from that of chloride of lime. Dissolve 20 lbs. of chloride 

 of lime in 200 lbs. water, and mix them with a solution of 

 24 lbs. Glauber salts in 100 lbs. water. When the mixture 

 has become clear, the clear solution should be removed 

 from the sediment, and 1 to 2 lbs. potash dissolved in water 

 added to it. 



This solution (chloride of soda) acts, when diluted with 

 water, slowly as a bleaching substance, but with certainty, 

 and sinks deep into the fibre. 



When solutions of chlorine are kept in wood, they cor- 

 rode the latter, and lose their bleaching power. This may 

 be prevented by a coating of two parts wax to one colopho- 

 nium. 



Bran is employed to cleanse prints and dyed stuffs, and 

 also as an addition to the dye solution. 



Bran for cleansing Prints.— It will be shewn, when treat- 

 ing of cow-dung, that mordants for delicate colours, as yel- 

 low, pink, lilac, &c, cannot stand cleansing with cow-dung. 

 Bran can be employed in these cases with advantage. It 

 has a similar action to the cow-dung, in so far that it ren- 

 ders insoluble, and precipitates those parts of the mordant 

 which are not intimately combined with the cotton, by 

 which they will be prevented from collecting in those parts 

 which should remain white. 



