174 



DYKE 



in a suitable solvent (acetic acid or alcohol) is all that is necessary. In the case of 

 the rosaniline salts, however, a neutral solution and a temperature not exceeding 

 180 F. are requisite. 



In dyeing vegetable fibres, albumen, glutin, gelatine, casein, tannin or tannic 

 acid, &c. are used as mordants. 



In printing with these colours the process is the same as in the case of steam 

 colours. Either the mordant is first printed on the fabric, which is then steamed and 

 dyed, or the colouring matter is thickened with the mordant (albumen, &c.), the 

 fabric dyed with this, and then steamed so as to fix it. 



Aniline Black has been quite recently produced by the direct oxidation of aniline 

 on cotton fibre. A mixture consisting of an aniline salt, perchlorido of copper, and 

 chlorate of potash, is printed on the cotton, which is then exposed to an atmosphere 

 of steam. After some time a black is developed. 



The following figures show the rapidity with which aniline and its derivatives 

 have fallen in price during the last few years, and thus give an idea of their rapid 

 industrial development : 



Aniline and Colours. Average Prices. 



DYER'S AIiXAWET, Anchiisa tinctoria. See ALKANET. 



DYER'S MADDER, Eubia tinctorum. See MADDER. 



DYER'S OAK, Quercus infcctoria. See GALLS and OAK. 



DYER'S GRCHEXiIiA WEED, Roccclla tinctoria. See ARCHIL ; ORCHELLA. 



DYER'S SAFFIiOWER, or Bastard Saffron. The Carthamus tinctoriv.s. The 

 flowers are of a deep orange colour, but they are used for dyeing various shades of 

 red. The flowers of the carthamus are employed in Spain for colouring dishes and 

 confectionary. See CARTHAMUS. 



DYER'S WOODROOP. Asperula tinctoria. The roots of this plant are used in 

 some parts of Europe, particularly Dalmatia, instead of madder for dyeing wool and 

 cloth of a reddish colour ; but in bulk the crop obtained is inferior to that of the 

 madder. Lawson* 



DYKE. (Scot, a wall or fence.) Applied to those wall-like intrusions of igneous 

 rock which fill up rents and fissures in the stratified rocks. They may sometimes fill 

 up pre-existing rents and fissures, but they usually burst through and displace the 



770 





rocks through which they are forced. Dykes are generally understood to bo connected 

 with the volcanic rocks below, from which they have been forced, in a molten ?t;itc, 



