" Button-lac " differs from shellac only in form. Instead of being drawn over a cylinder, the melted lac is allowed to fall upon a plane, and assumes the shape of large, flat, gingerbread-nuts, about 3 in. diam. and * in. thick. The manufacture of lac-dye is described on pp. 861-2.
Elliott Angelo, of Cossipore, has adopted improved methods and machinery in his factory. The first of these is in the washing department, where steam-driven cylinders with internal rotating arms are used. The macerated seed-lac is melted in closed steam-heated vessels, with addition of rosin, which is said to act as a flux and a preventive of burning, and subsequently to evaporate. The cylinders for making shellac are formed of zinc, and maintained at an equable temperature by internal pipes supplied with tepid water. Lac is frequently adulterated with orphnent, which imparts a fine yellow colour ; and very largdy (up to 50-60 per cent.) with common rosin. The latter may be readily detected by its odour on breaking the mass. The chief grades are " fine orange D C,'' " liver," " garnet," " native leaf," and " button." The approximate relative market values in London are :—Orange, 65-200s. a cwt. ; liver and native orange, 65-175s. ; garnet, 60 155s. ; button, dark to middling, 60-180s. ; button, good to fine, 70-200s. ; seed-lac, 80-90s. ; stick lac, Siam, 45-140s. In India, lac is used chiefly in the manufacture of various trinkets. In Europe, it is largely employed in the preparation of spirit-varnishes, cements, lithographic ink, and sealing-wax, and as a stiffening for hats. White shellac is usually kept in water, by which means, its capability for solution is preserved. This property is lost withal a fortnight of its preparation, by exposure to the air ; within the period, it is readily soluble in naphtha or " finish." The trade iu lac is extensive, Our imports of seed, shell, stick, and dye lac have been :— 98,855 cwt., 530,017/., in 1876 ; 100,442 cwt., 395,831/., in 1877 ; 79,593 cwt., 273,923/., in 1878 ; 51159 cwt , 179,305/., in 1879 ; 58,081 cwt., 369,317/., in 1880. The imports of 1880 were contributed as follows ; —Bengal and Burma, 54,179 cwt., 347,998/.; other countries, 3902 cwt., 21,3191. ; total, 58,081 cwt., 369,317/. Our imports from Bengal and Burma fell from 95,058 cwt., in 1877, to 47,368 cwt. in 1879, and only recovered to 54,179 cwt. in
1880. Our imports from the Stmits Settlements fell from 5228 cwt. in 1876, to 541 cwt. in 1879, and only recovered to 832 cwt. io 1880. Our re-exports io 1880 were :—Te the United States, 14.9s9 cwt., 70,2231. ; Germany, 10,458 cwt., 61,542/. ; Holland, 4200 cwt., 23,3361.; Russia, 2801 cwt., 16,3191.; France, 2653 ewt., 17,9461.; other countries, 4124 cwt., 21,984/. ; total, 38,025 cwt., 211,3601. It is necessary to repeat that all these figures include lac dye. The Indian exports, excluding lac dye, were :-68,264 cwt. in 1875, 92,915 in 1876, 109,661 in 1877, 95,07:1 in 1878, 83,162 in 1879. The relative proportions of the several kinds in 187.5-6 were :—Shellac, 80,645 cwt. ; stick-lac, 207 cwt.
There remains to mention under this head the discovery of the same or a very closely allied insect, capable of affording the same product, in sonic portions of the United States. The planta on which the insect has been fonad are Acacia Greggii, and the creasote bush, stinkweed, or etiontie (Larrea mexicana). These plants flourish abundantly from S. Utah to New Mexico, and from the Colorado Desert to W. Texas, wherever the rainfall amounts to 3 in. annually. The second apecies is particularly common en the hills bordering the Gila, and on the sandy wastes adjacent to Tucson and Camp Lowell, in Arizona. With care and cultivation, there seems to be ne reason why these natural resources should not be developed so as to render America independent of foreign supplies of shellac.
Lignum Perfumes—Agar, pp. 1523-4.
Sterax, pp. 1682-3.
mahogany tree, Swietenia Mahogani Timber), under celtivation in Bom bay, affords an abundaoce of a superior silvery-leeking gum, of which no use seems to he made.
wounding the bark of the mango (Mangifera indica), which is common everywhere in India, there exudes a soft, reddish-brown gum-resin, hardening by age, and much resembling bdellium. It is often mottled in such a way as to lead to its confusion with asafcctida (the hing variety), or with amygdaloid benzein. It has a strong and persistent odour of ripe mangoes, and emits a smell of roasting cashew-nuts when burnt in eandle-tlame. It dissolves partially in water, and completely in spirit. It is used medicinally by the natives of Iodia.