BRAZIL WOOD

brazil wood, a dye wood of commercial importance, obtained from the west indies and south america, belonging to the genera _caesalpinia_ and _peltophorum_ of the natural order leguminosae. there are several woods of the kind, commercially distinguished as brazil wood, nicaragua or peach wood, pernambuco wood and lima wood, each of which has a different commercial value, although the tinctorial principle they yield is similar. commercial brazil wood is imported for the use of dyers in billets of large size, and is a dense compact wood of a reddish brown colour, rather bright when freshly cut, but becoming dull on exposure. the colouring-matter of brazil wood, brazilin, c16h14o5, crystallizes with 1-1/2 h2o, and is freely soluble in water; it is extracted for use by simple infusion or decoction of the coarsely-powdered wood. when freshly prepared the extract is of a yellowish tint; but by contact with the air, or the addition of an alkaline solution, it develops a brick-red colour. this is due to the formation of brazilein, c16h12o5.h2o, which is the colouring matter used by the dyer. brazilin crystallizes in hexagonal amber yellow crystals, which are soluble in water and alcohol. the solution when free of oxygen is colourless, but on the access of air it assumes first a yellow and thereafter a reddish yellow colour. with soda-ley it takes a brilliant deep carmine tint, which colour may be discharged by heating in a closed vessel with zinc dust, in which condition, the solution is excessively sensitive to oxygen, the slightest exposure to air immediately giving a deep carmine. with tin mordants brazil wood gives brilliant but fugitive steam reds in calico-printing; but on account of the loose nature of its dyes it is seldom used except as an adjunct to other colours. it is used to form lakes which are employed in tinting papers, staining paper-hangings, and for various other decorative purposes.