The Engineer's and Mechanics Encyclopædia: Weld or Woald.

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.
London: Thomas Kelly, 17, Paternoster Row.
A plant cultivated in many parts of this kingdom, for its yellow colouring matter. Two sorts of weld are distinguished, the bastard or wild, which grows naturally in the fields; and the cultivated, the stalks of which are smaller and not so high. The latter is preferred for dyeing, abounding more in colouring matter. When the plant has arrived at maturity the stalks are pulled, made into bundles and dried, in which state it is used. To give a permanent yellow to wool by weld, mordants become necessary; but when prepared with alum and tartar, it takes a very durable and fine yellow.

Ei kommentteja :