DYEING 



163 



illustration. Among the metals permanent in the air, 17 are ductile and 16 are brittle. 

 But the most ductile cannot be wire-drawn or laminated to any considerable extent 

 without being annealed from time to time during the progress of the extension, or 

 rather the sliding of the particles alongside of each other, so as to loosen their lateral 

 cohesion. See MALLEABILITY. 



Table of the Ductility and Malleability of Metals. 



DUXiSE. The Eliodymenia palmata. See 



DUNES. Low hills of blown sand, which are seen on the coasts of Cheshire and 

 Cornwall, in this country, and also in many places skirting the shores of Holland and 

 Spain. 



DUNGING, in calico-printing, is the application of a bath of cow-dung, diffused 

 through hot water, to cotton goods in a particular stage of the manufacture. Dunging 

 and scouring are commonly alternated, and are two of the most important steps in the 

 process. See CALICO-PRINTING. 



DUNSTONE. Magnesian limestones of a dun colour, occurring near Matlock in 

 Derbyshire. 



DUTCH FOIXi, ZiEAF, or METAXi. A composition of copper and zinc, or of 

 beaten bronze or of copper leaf. See ALLOYS ; BRASS ; and BRONZE POWDERS. 



DUTCH liXQUXD. A name given to an oily substance produced by the action 

 of chlorine on olefiant gas. It was discovered at the close of the last century by an 

 association of Dutch chemists. 



DUTCH RUSH. Equisetwm hyemale. This rush is known also as the Large 

 branchless Horse-tail. The dried stems are much employed for polishing wood and 

 metal. For this purpose they are generally imported from Holland. 



DYEING (Tdnture, Fr. ; Fdrberei, Ger.) is the art of imparting to and fixing 

 upon wool, silk, cotton, linen, hair, and skins any colour, with sufficient tenacity not 

 to be removed by water or the ordinary usage to which these fibrous bodies are 

 exposed when worked up into articles of raiment or furniture. We shall here consider 

 the general principles of the art, referring, for the particular dyes and the manner of 

 treating the stuffs to be dyed, to the different tinctorial substances in their alphabetical 

 order. 



Dyeing, although altogether a chemical process, and requiring for its correct ex- 

 planation an acquaintance with the properties of the elementary bodies, and the laws 

 which regulate their combination, has been practised from the most ancient times, 

 long before any just views were entertained of the nature of the changes that took 

 place ; and it is still practised by many who know very little of chemical science : 

 indeed, like many of the other chemical arts, its practice is often in advance of the 

 science by which its principles are explainable. The art no doubt originated in that 

 love of distinction inherent in the human mind, inducing man, for its gratification, 

 to stain his dress or his skin with the gaudy colours of the vegetable kingdom. The 

 earliest historical record speaks of coloured garments being worn as marks of dis- 

 tinction for offices both political and religious, and also as marks of favour. Jacob 

 gave his favourite son Joseph a coat of many colours, and Moses speaks of a raiment 



M 2 



