_Djaft_, _dchift_, _jift_, or _jaft_ is a material apparently of Eastern origin, and said to be derived from an oak of Kurdistan. Dark red scales or fragments, origin uncertain, very astringent and darkish tannage, liquor when spilt dries whitish, apparently from crystallisation of some sort. It contains a large amount of tannin. It appears very irregularly in commerce and the writer would be glad to obtain further samples and details of origin. He once used 6 or 7 tons successfully in sole-leather tannage. It has also been attributed to a shrub allied to the _Cæsalpinias_ (p. 286). The most important American oaks are--_Q. prinus_ (_castanea_, _monticola_), the Chestnut or Rock Oak (Fig. 51). About equal to our oak in strength, bark very thick, and infusion strongly fluorescent, especially in presence of ammonia. Source of chestnut-oak extract. The most important tanning oak-bark of the United States. _Q. alba_, or “white oak,” is perhaps the most widely distributed and abundant of any of the American oaks, and very closely resembles the European _Q. robur_. _Q. tinctoria_ or _nigra_, Black or Quercitron Oak. Poor as a tanning material, but used for dyeing yellow, and for modifying the colour of hemlock tannages. The dyestuff, _quercetin_, is closely allied to that of fustic, and gives yellows with alum and tin mordants. A good deal of information is given by Trimble[138] on American oaks and other tanning materials. [138] ‘The Tannins,’ vol. ii., Lippincott, Philadelphia, 1894. Important Indian oaks are _Q. glauca_, _Q. lamellosa_ and _Q. incana_; bark of last said to yield 22 per cent. of tannin. SALICACEÆ, Willows. The bark of various willows, especially _Salix arenaria_ and _Russeliana_, is used for tanning in Russia, and for Danish glove-leather. Some contain up to 12-14 per cent. of an iron-blueing tannin. They impart a strong odour to leather, but different to that of birch-tar oil, and the scent of genuine Russia leather is due to a combination of both. In many cases the bark peeled off osiers for basket-making is employed. A Russian willow (species unknown), in the form of thin bark of osiers or small branches, gave 9·5 per cent. tannin when examined in the Leather Industries Laboratory of the Yorkshire College; and willow barks certainly demand more attention than they have received in England as tanning materials for fine leathers. _Salix caprea_ has been used in France for glove leathers, but is weaker than _S. arenaria_. Poplars belong to the same natural order, and have been used for tanning, but their barks at the most contain 2-3 per cent. POLYGONACEÆ, Docks. Most members of this family contain tannin.