In China trade returns, they are always miscalled "nut-galls" or "gall-nuts": correctly, they are wu-pei-tze. Oak-galls are exported from China resembling those of Western Asia. Japanese galls, kifushi, are sent in increasing quantities from Hiogo.
Our imports of galls in 1880 were:—24,590 cwt., 68,697l., from China; 17,311 cwt., 60,648l., from Turkey; 9182 cwt., 9013l., from other countries: total, 51,083 cwt., 138,358l. Our re-exports in the same year were:—6260 cwt., 18,479l., to Holland; 6022 cwt., 18,147l., to Germany; 3214 cwt., 11,002l., to France; 3045 cwt., 8598l., to Belgium; 2651 cwt., 11,004l., to the United States; 1625 cwt., 5205l., to other countries; total, 22,817 cwt., 72,435l. The approximate London market values of galls are:—Bussora, blue, 82-102s. a cwt.; do., white and in sorts, 50-90s.; China, 50-70s.; Japan, 55-56s.
Gambier, Pale Catechu, or Terra Japonica (Fr., Gambir, Cachou jaune; Ger., Gambir).—These names are conferred upon an extract from the leaves of Uncaria Gambier [Nauclea Gambir] and U. acida, containing 36-40 per cent. of a brown tannin, which rapidly penetrates leather, and tends to swell it, but alone gives a soft porous tannage; it is largely used in conjunction with other materials for tanning both dressing- and sole-leather. The plants are stout climbing shrubs, the first-named being a native of the countries bordering the Straits of Malacca, and especially the islands at the eastern end, though apparently not indigenous to any of the islands of the volcanic band, growing also in Ceylon, where no use is made of it; while the second, probably a mere variety, flourishes in the Malay islands.
The shrubs are cultivated in plantations, often formed in jungle clearings; the soil is very rapidly exhausted, and further injured by excessive growth of the ineradicable lalang-grass (Andropogon caricosus). It is found advantageous to combine pepper-culture with that of gambier, the boiled leaves of the latter forming excellent manure for the former. The gambier-plants are allowed to grow 8-10 ft. high, and as their foliage is always in season, each plant is stripped 3 or 4 times in the year. The tools and apparatus for the manufacture of the extract are of the most primitive description. A shallow cast-iron pan about 3 ft. across is built into an earthen fire-place. Water is poured into the pan, a fire is kindled, and the leaves and young shoots, freshly plucked, are scattered in, and boiled for about an hour. At the end of this time, they are thrown on to a capacious sloping trough, the lower end of which projects into the pan, and are squeezed with the hand so that the absorbed liquor may run back into the boiler. The decoction is then evaporated to the consistence of a thin syrup, and baled out into buckets. When sufficiently cool, it is subjected to curious treatment: instead of simply stirring it round, the workman pushes a stick of soft wood in a sloping direction into each bucket; and, placing two such buckets before him, he works a stick up and down in each. The liquid thickens round the stick, and, the thickened portion being constantly rubbed off, while at the same time the whole is in motion, it gradually sets into a mass, a result which, it is said, would never be produced by simple stirring: it is reasonable to suppose that this manner of treating the liquor favours the crystallisation of the catechin in a more concrete form than it might otherwise assume. The thickened mass, resembling soft yellowish clay, is now placed in shallow square boxes; when somewhat hardened, it is cut into cubes, and dried in the shade. The leaves are boiled a second time, and finally washed in water, which is saved for another operation.
A second plan is as follows:—The leaves are boiled, and bruised in a wooden mortar (lesong), from which they are put into a kind of basket of rattan open-work, which is pressed by a long piece of wood acting as a lever; the liquid is received into a trough, and there allowed to settle. When the sediment has acquired sufficient substance, it is put into a kulit-kayo, formed like a tub without a bottom, which lets the superfluous water drain off; when that is done, it is taken out, made into small cakes, and dried for use. A plantation employing 5 labourers contains 70,000-80,000 shrubs, and yields 40-50 catties (of 11/3 lb.) of gambier daily.
Plantations were commenced in Singapore in 1829, and once numbered 800; but owing to scarcity of fuel, abundance of which is essential to the manufacture, and dearness of labour, the culture was fast declining in 1866. In 1872, it had much recovered. It is largely pursued on the mainland (Johore), and in the Rhio-Lingga Archipelago, S.-E. of Singapore; on Bintang, the most northerly of the group, there were 1250 plantations of it in 1854. None is cultivated in Sarawak, though found wild in many parts; the foreign export from Sarawak in 1879 had a total value of 88,148 dol. The best kind is brought largely from Sumatra, but is often adulterated with sago. The Rhio product is also thus sophisticated, and rendered heavier by the Chinese purposely packing it in baskets lined with wet cajangs, occasioning a loss to the purchaser of about 30 per cent.
Singapore is the great emporium for gambier, and exported 34,248 tons in 1871, 19,550 tons having been imported, chiefly from Rhio and the Malay Peninsula. In 1876, the export increased to over 50,000 tons of pressed block, and 2700 tons of cubes. In 1877, it fell to 39,117 tons, owing to differences with the Chinese dealers concerning adulteration; of this quantity, 21,607 tons were for London, 7572 for Liverpool, and 2345 for Marseilles. The United Kingdom imports in 1872 were 21,155 tons, 451,737l., almost all from the Straits Settlements; in 1880, they were 26,061 tons, 461,781l., from the Straits, and 352 tons, 6468l., from other countries; total, 26,413 tons, 468,249l. Our re-exports in 1880 were:—2487 tons, 48,507l., to Holland; 1591 tons, 31,542l. to Germany; 1137 tons, 23,694l., to Russia; 594 tons, 12,026l., to other countries; total, 5809 tons, 115,769l. The approximate London market values are 15s. 6d.-21s. 6d. a cwt. for block, 18-24s. for pressed cubes, and 23-27s. for free cubes.
Hemlock.—The bark of the hemlock or hemlock spruce (Abies canadensis), of Canada and the United States, contains nearly 14 per cent. of tannin. The stripping of the bark commences in the southern parts of the United States in spring, and lasts during April-May; in New York, Michigan, and Wisconsin, the season is June-July; and farther north, it is still later. It is said that the best product is obtained farthest south. The destruction of the hemlock forests is fast approaching. Within the last 25 years, the preparation of an extract from the bark, containing 18-25 per cent. of a deep-red tannin, giving considerable weight and firmness to leather, has superseded the export of crude bark. One mode of preparing the extract is as follows:—The bark in pieces 1/2-1 in. thick, and several inches long, is soaked for about 15 minutes in water at 200° F. (93° C.); it is then fed into a hopper, which conducts it to a 3-roller machine, something like a sugar-cane mill, through which it passes, coming out lacerated and compressed; it next falls into a vat of hot water, where it is agitated by a wheel, that the tannin from the crushed cells may be dissolved in the water; hence it is raised by a series of buckets on an endless chain, somewhat in the manner of a grain-elevator, to another hopper, whence it is fed to another 3-roller mill; here it receives its final compression, and comes out in flakes or sheets, like coarse paper, and almost free from tannin. The buckets are made of coarse wire, that the water may drip through during the elevation. In order to avoid the blackening action of iron, wherever this metal will come into contact with the solutions it is thickly coated with zinc. The solution is evaporated to a solid consistency, generally by vacuum-pans. About 2 tons of bark are represented by 1 bar. (of less than 500 lb.) of extract. The chief makers are A. S. Thomas, Elmira, N.Y.; S. Brown & Co., New York; Canada Tanning Extract Co., St. Leonard and Bulstrode; J. Miller & Co., Millerton, New Brunswick. The total production is probably over 10,000 tons annually, ranging in value between 14l. and 20l. a ton. Our imports are included in barks and extracts.
Kino (Fr., Kino; Ger., Kino).—The term "gum kino" is applied to a class of astringent extracts of varied origin, none of which can accurately be called either resins or gums.