The Engineer's and Mechanics Encyclopædia,
comprehending practical illustrations of the machinery and processes employed in every description of manufacture of the British Empire.
With nearly Two Thousand Engravings.
By Luke Hebert, civil engineer, edifor of the History and Progress of the Steam Engines, Register of Arts and Journal of Patent Inventions, etc.
In two volumes.
VOL. II.
London: Thomas Kelly, 17, Paternoster Row.
MDCCCXXXVI (1836).
A substance very extensively employed in dyeing; it is the root of a trailing plant that grows very abundantly in the south of Europe. It is cultivated in England and Holland also; but the best is said to be that brought from Smyrna and Cyprus. The roots of the plant are carefully peeled, dried in the air, and afterwards in a kiln, in the same way as hops are dried in Kent. They are then chipped and pulverized. The best roots are about the thickness of a goose-quill; semi-transparent, of a reddish colour and strong smell. The red colouring matter of madder is soluble in alcohol, which, on evaporation, leaves a residuum of a deep red. Fixed alkali forms in this solution a violet, the sulphuric acid a fawn coloured, and the sulphate of potash a fine red precipitate. A variety of shades are obtained by the addition of alum, chalk, nitre, sugar of lead, and the muriate of tin.
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