Trees of about 1 foot diameter are cut down, and the wood (some state the heart-wood only) is reduced to chips, and boiled with water in earthen jars over a mud-fireplace. As the liquor becomes thick and strong, it is decanted into another vessel, and the evaporation continued till the extract will set on cooling, when it is poured into moulds made of leaves or clay, the drying being completed by exposure to the sun and air. “Kath,” or pale cutch, is made in Northern India, by stopping the evaporation at an earlier point, and allowing the liquor to cool, and crystallise over twigs and leaves thrown into pots for the purpose. It contains a large proportion of catechin, apparently identical with that of gambier, but its tannin is much redder. Good cutch contains about 60 per cent. tanning matter, but is principally used for dyeing browns and blacks with chrome and iron mordants. It contains quercetin, a yellow colouring matter (p. 263). _A. leucophlea_, India and Java “_Pilang_.” Pods and bark equal to _A. arabica_. Australia abounds in acacias (mimosas), many of which are used in tanning, but vary greatly in strength, not only according to species, but probably also by situation and growth. Probably the best information is to be found in a pamphlet on ‘Wattles and Wattle-Bark,’ by J. H. Maiden, F.L.S., published by the Department of Public Instruction at Sydney, 1890. His analyses were made by the Löwenthal process, and can only be roughly compared with those by the hide-powder method. The analyses given are by the I.A.L.T.C. method, and mostly on samples furnished by Mr. Maiden. A peculiarity largely developed in the mimosa family is the tendency for the true leaves to be suppressed, and their place taken by the flattened and expanded midrib (phyllode). Thus leaves of two very distinct forms are common in the genus, and some acacias, as _A. heterophylla_, may have both forms on the same branch. Compare _A. pycnantha_ and _A. decurrens_. The Australian mimosas have been naturalised in India, and grow freely in the Nilgiri Hills, but the bark does not appear to be utilised. The most important species are as follows:-- _A. pycnantha._ (Fig. 61.) “Broad-leaved” or “Golden Wattle,” South Australia. One of the strongest tanning barks known. A sample marked “special,” analysed in the Yorkshire College, contained 50 per cent. of tannin; another sample marked “ordinary” contained 40 per cent. [Illustration: FIG. 61.--Broad-leaved Wattle (_Acacia pycnantha_).] [Illustration: FIG. 62.--Green Wattle (_Acacia decurrens_).] _A. longifolia_, the Golden Wattle of New South Wales, only contains half as much tannin as _A. pycnantha_.