Bakau or Tengah bark of the East Indies, " Goran" of Bengal. It contains up to 27 per cent of tannin and yields an extract which promises well as a substitute equal to cutch, for dying purposes. The solid extract contains up to 65 per cent of tannin, making a good but dark red leather. Ceriops Roxburghiana bark is very similar in strength and character to the above.
Eucalyptus barks.
Blue gum (Eucalyptus Clobulus) and other species of Eucalyptus are common in Australia. Blue gum has been introduced into the United States, in southern California and Arizona, and is found in Algeria and southern Europe. The Eucalyptus is more or less rich in catechol tannins, the sap being the source of Botany Bay or Australian kinos, which contain up to 79 per cent of tannin. Sev eral species of Eucalyptus afford astringent extracts ; those from the "red," "white," or "flooded" gum (E. rostrata), the "blood-wood" (E. corymbosa), and E. eit riodora, being quite suitable for replacing the official kind. The bark of E. occidentalis contains 35-50 per cent of tannin and is now being used under the name Mallet bark, from which the tannin is readily soluble. It makes a light brown leather. The bark of E. longifolia, the "woolly-butt" of Australia, contains 8.3 per cent of tannic acid, and 2.8 of gallic acid. The bark of the "peppermint" tree contains 20 per cent of tannic acid. The "stringy-bark" (E. obliqua) gives 13i per cent of kinotannic acid. The Victorian "iron-bark" (E. leucory ion) contains 22 per cent of kinotannic acid, but is avail able only for inferior leather.
ansalpinia.
Divi-divi (Cresalpinia Coriaria). This is a tree of 20 30 feet high, native in central America and introduced suc cessfully into India. The dried pods contain 40-45 per cent of a pyrogallol tannin, mainly ellagitannic acid, and would he a most valuable tanning material but for a lia bility to fermentation and sudden development of a deep red coloring matter. If used in strong liquors it gives a heavy and firm leather, but is principally employed as a partial substitute for gambier on dressing leather. The seeds do not contain tannin. Tari or teri pod (C. digyna) occurs in parts of India and Burmah, where it is used as a drug. The pod-case is said to yield over 50 per cent of tanning material. C. digyna promises to become a valuable tanning material if it proves free from the tendency to ferment. It yields a leather quite as white as sumac. Cas calote (C. Cacalaeo) is found in Mexico. The pods are rich in tannin, in some instances containing 55 per cent. The tannin is similar to that of divi-divi.
Algarobilla (C. [or Balsainocarpon] brevifolia) is found in Chile. This is one of the strongest tanning ma terials known, containing an average of 45 per cent of a tannin very like that of divi, but less prone to discolora tion. The tannin lies loose in a very open skeleton of fiber, and is easily soluble in cold water ; the seeds con tain no tannin.
Logwood (C. [or Hcematoxyloni Campechianum) is found in Central America. It contains about 3 per cent of tannin. Its principal use is in dyeing blacks with iron or chorme mordants.
Cassias.
Turwar or Tanghadi bark (Cassia auriculata) is found in southern India. It is used for tanning so-called "Persian" sheep and goat-skins, and contains about 17 per cent of a catechol tannin. Leather tanned with it is of a pale yellow color, but rapidly reddens in sunlight. a Fistula is found in India. The husk of the pod contains 17 per cent tannin.
Mimosas.
" Babool," or "Babul" (Acacia Arabica), is found in India and Egypt. The bark contains about 12 to 20 per cent of catechol tannin and considerable red coloring matter. It is extensively used in India for tanning kips and heavier leathers. The pods contain about the same amount of tannin as the hark but of a different kind.
Cutch is derived from the wood of A. Cala/in of India. A lighter colored variety called kath is made in northern India, and used principally for chewing with betel. The extract or cutch is made by boiling the chips 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 until 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 catch, is made by stop ping the evaporation at an earlier point and allowing the li iu 'r to cool and crystalize over twigs and leaves thrown into pots for the purpose. Good catch contains about 60 per cent of tanning matter, and is principally used for dyeing browns and blacks with chrome and iron mordants. It contains quercetin, a yellow coloring matter. "Pilang" (A. leurophl,ra) is found in India and Java. The pods and bark contain about as much tannin as A. Arabica. "Golden wattle," or "Broad-leaved wattle" (.4. pyc nantha), is found in South Australia. It has one of the strongest tanning barks known, containing 30 to 50 per cent of tannin. It has been cultivated successfully in Cal ifornia and Hawaii. The Golden wattle (.4. long ifolia), of New South Wales, contains only half as much tannin as .4. pyenantha. Black wattle (.4. mollissinta), with its two varieties, A. decurrens and A. dealbata, is among the most important of the Wattle family commercially. The bark contains 30 to 50 per cent of tannin and is grown successfully in Natal and in California. Hickory bark (.4. penninervis) contains about 30 to 40 per cent of tannin. A. binerrata, another Black wattle, contains up to 30 per cent of tanning matter, as does also the Weeping willow (A. saligna). The bark of A. prominens contains 14 per cent of tannin.