BRAZIL, wood, in the arts. The tree which bears this wood is the cxsalpina crista. The wood is very hard, takes a high polish, and is so heavy as to sink in water. When chewed it gives a sweetish taste. It much resembles in appearance red minders wood, but differs from it es sentially in readily giving out its colour to water, which minders wood does not.
Brazil wood is valuable for the beautiful orange and red colours, in various shades, which it furnishes to the dyer, but the colour is naturally very fugitive, though it may be to a certain degree fixed by va rious mordants. When raspings of Bra zil wood are boiled for some time in wa ter, they give a fine red decoction. The residue appears black, but alkalies will continue to extract a colour from it after the action of water is exhausted. Spirit of wine and ammonia also extract a co.. lour with great facility, which is some what deeper than the watery decoction. A decoction of Brazil wood is readily turned of a violet or purple blue by alka lies, and this change is produced by so very minute a quantity, as to furnish a chemical test of the presence of alkalies of very great utility. According to Berg mann, 10 grains of crystallized carbonate of soda, which contains no more than about 2.15 grains of mere alkali, dissolv ed in something more than 5.5 English pints of water, give a sensible purple paper reddened by Brazil Wood. There is, however, some ambiguity in this test, as the same change is produced by a solution of lime or magnesia in car bonic acid and water, a very frequent oc currence in most natural waters. Evapo rating the water for some time will dis tinguish whether the change on brazil wood is produced by an alkali, or a car bonated earth ; for, if by the former, the purple will be more intense in the concen trated water, as it now holds a greater pro portion of alkali ; but if by a carbonated earth, the effect will be lost, as the boiling expels the loose carbonic acid, and preci pitates the carbonated earth which it held in solution. The effects of the solutions
of tin and alum on brazil wood are the most important to the dyer. Alum added to the watery decoction of the wood gives a copious fine redprecipitate, inclining to crimson, and subsiding slowly. The su pernatant liquor also retains the original red colour of the decoction, but if enough of alkali is added to decompose the alum, its earth falls down, and carries with it nearly all the remaining colouring matter of the wood. In this way a fine crimson lake, i mitating the cochineal carmine, may be prepared, which therefore consists of alumine, intimatelycombined with the co louring matter of the wood a little height ened. Nitro-muriate of tin added to the decoction separates the whole of the co louring matter, which falls down in great abundance in union with the oxide of tin, and the liquor remains colourless.
The solutions of iron blacken the de coction or infusions of brazil wood, sheav ing the presence of the gallic acid. Ma ny of the other metallic solutions act si milarly to that of tin, in forming lakes, consisting of the colouring matter of the wood united with the metallic oxide of the solution employed. See DYEING.