440 [Assembly 



Colors are either simple or compound. Among the simple may 

 be classed blue, yellow and red — neither of these can be produced 

 by mixing sundry colors together. On the other hand, compound 

 colors may be made by mixing colors together in proportions. 

 Purple may be formed by mixing blue and red ; orange, by mix- 

 ing yellow and red ; green, by mixing blue and yellow. 



It is important in dyeing, that the water made use of should be 

 pure. Earthy salts in water have a serious effect upon colors, 

 sufficient to prevent them from combining with cloth. Water 

 that possesses no taste is the best. In dyeing blue, the coloring 

 matters generally employed are woad and indigo. Woad is a 

 biennial plant, growing wild in many parts of England. The 

 ancient Britons are said to have painted their bodies with the 

 blue colors obtained from it. The natural plants are less 

 smooth, and not by any means so luxui-iantas the cultivated ones. 

 The root of this plant is tapering. The stem groAvs to the height 

 of two feet, is slightly glaucous, and panicled at the top. The 

 radical leaves are crenate, and those of the stem sessile. Panicle 

 of compound racemose branches, covered with lanceolate leaves, 

 all of a yellow color and likewise the stalks. 



When cultivated in rich earth, and kept entirely free from 

 weeds, it becomes a large plant, with very fine bluish-green leaves, 

 branching stalks, covered with multitudes of flowers ; the seed 

 is oval. When the leaf is full grown, firm, juicy, and present- 

 ing a fresh, fine green, it is fit for gathering, and should be 

 plucked at once and sent to the mill. The farmer must then 

 prepare for his next crop, as it yields several in the course of the 

 year. It will stand for some years, and continue to produce, but 

 ghould be renewed every second year. An acre will grow one 

 ton. It is raised from the seed. In dyeing wool blue, woad and 

 bran are used as ferments, and lime as a solvent of the green 

 base. Woad contains coloring matter similar to indigo, but not 

 in such a large quantity. 



When cloth is to be dyed in a woad vat, the bath should be 

 stirred two and a half hours before it is immersed ; it must be 

 prevented from coming in contact with the sediment at the bot- 

 tom of the vat by means of a netting. 



