SANTAL WOOD.

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colours upon wool and silk, and even for dyeing, has been in some casessuperseded by the new aniline colours, but they are used for clarets and brownsalong with orchil and other colouring matters. They are also largely used indyeing so-called “ mock crimsons,” in imitation of those produced withcochineal. In scarlet and crimson coburgs, and other mixed goods, the cottonwarp is got up with a wood of this class in conjunction with a per-salt of tin.The best method of testing the woods, or the extracts thereof, for their valueis a mode of assay founded upon either a dyeing or printing process, con-ducted as follows :—Take io grms. of the material to be tested, if woodit must be previously pulverised, and also a piece of 25 square centimetres ofcotton cloth, mordanted, as indicated above, for testing garancin ; put thesematerials into a suitable glass vessel, wherein is poured \ litre of water; heatthe vessel in a water-bath, and keep the dyeing process up for half an hour,care being taken to stir the contents of the vessel about with a glass rod.The pattern, after having been washed with cold water, is placed for sometime in a bran-bath, at 8o°, and afterwards again washed with cold water, anddried. This mode of testing requires the use of a standard sample for com-parison.

Commercial samples of ground woods often,contain an excess of moisture.If on drying at 212 0 F. the loss exceeds 32 per cent, there is good cause forcomplaint. If allowed, when very moist, to lie long in large heaps, heat isdeveloped, and the colouring matter is gradually destroyed. The extract, atio° Baume (sp. gr. 1*075), is about five times as strong as the wood.

If preferred, the following colour mixture may be made up :—ExtraCt of thewood, 20 grms.; alumina mordant, 200 grms.; water, 140 grms.; pulverisedgum, 160 grms. After the latter substance has been dissolved the fluid shouldbe passed through a fine sieve. This mixture is printed on -by means of aroller; if calico, by means of block-printing; if muslin is the fabric uponwhich it is desired to test, after drying the fabric so treated is steamed andwashed. This assay also requires a standard sample of extract.

. The red dyes produced by these woods or extracts, and fixed upon fabrics,are recognised by the following tests :—Like the reds produced by madder andcochineal, they are destroyed by chlorine and hypochlorous acid : on incine-ration they leave a compound of alumina or tin, according to the mordantemployed ; but the reds produced by the woods are also destroyed by boilingsoap solution, which distinguishes them from madder reds. When successivelyimmersed, first in hydrochloric acid, and next in lime-water, the red woodshades are turned violet, which is destroyed by boiling soap solution. Con-centrated sulphuric acid turns the red of the woods to deep cherry-red, whileit converts cochineal to an orange-yellow.

B. Close or Insoluble Class.

The principal woods of this class are santal wood, cam wood, and barwood. These woods are of a more resinous charadtef than Brazil wood andallies, yielding faster dyes, but from the insolubility of the colouringmatters they cannot be used in the state of extracts.

Sanders Wood, Santal Wood, or Red Sanders.

This wood is the produdl of Pterocarpus santalinus, a tree growing in India,^ e }lon, Timor, and other tropical parts of Asia. The wood is hard, of a