This kind of daramar usually occurs in commerce in nodules 1,-f in. diam., occasionally of much larger size. Tile exterior is coated with white powder from mutual attrition, while the mass is straw-coloured or pale-amber, transparent or translucent. It splita readily, and is very friable. It is acratched by copal, and some even by mica, but ia harder than rosin. It adheres only feebly by heating in the hand. It softena at about 100° (212° F.), and commences to melt at 150° (302 F.) to a clear liquid of agreeable resinous odour. The fracture is conchoidal and vitreous, and generally exhibits abundant air-bubbles and some vegetable d6bris. The resin splits and cracks at the temperature of the hand. The odour is balsamic when the resin is new ; afterwards imper ceptible. The flavour is slightly resinous ; sp. gr. 1.062-1.123. It yields a small quantity of lime to water ; is incompletely soluble in cold alcohol, moderately soluble in ether, soluble in boiling alcohol, fixed and volatile oils (especially turpentine- and boiling linseed-oils), chloroform, carbon bisulphide, benzol, and petroleum-spirit ; but insoluble in acetic acid, nitric acid, caustic soda, and ammonia.
It is extensively used in the manufacture of varnishes for coach-builders and painters, and in mounting microscopic objects, and has. long been recommended for making sticking-plaister. Inferior qualities are used in the locality of production for caulking ships and burning as incense ; also for illumination, when pounded and filled into tubes of di ied bamboo-stems or palm-leaves.
The exports of dammar (quoted as " gum mastic " in the Consular reports) from Manilla in 1879 were 1356 piculs (of 139i lb.) to Great Britain, and 550 to the Straits and India ; total, 1906 piculs, value, 1525/. And the value of the " gum " exported in 1880 was 9600/.
2. Sal Dammar.—This is produced by the sal tree, Shorea [Vatica] robusta (see Timber—Sal), in the tropical Himalaya, and along its base from Assam to the Sutlej, in the E. districts of Central India, in the W. Bengal hilla, and in Borneo and Sumatra ; also by this species or S. [V.] sericea in Malacca, and possibly by S. [V.] Tufnbuggaia [penicillata] in the W. Peninsula and the forests. of Cuddapa and Palghaut in Mysore. Sal dammar occurs ia brittle, stalactitic pieces, pale cream yellow, nearly opaque, each piece being striated, as if the resin had run out in thin liquid streams, and coagulated on the aurface one over another. Its sp. gr. is 1.097-1.123 ; it is easily fusible, par tially soluble in alcohol, almost completely in ether, perfectly in turpentine-oil and fixed oils, and more freely and speedily in benzol than in turpentine-spirit. Theae solutions are turbid. The turpentine solution (2 parts resin to 2i parts turpentine-oil) makes a good varnish for lithographic drawings, being clear, nearly colourless, and drying rapidly without cracking; also a moderately good tracing-paper. The resin occasionally appears in the English and Frenoh markets.
3. Black Dammar.—The black or kala dammar of India is derived from one or more species of Canarium, the chief being C. strictum. This tree is common in the Alpine forests about Courtalum, in the Tinnevelly district, and is there regularly rented for the sake of its daturnar. In this locality, the reain is obtained by making a great number of vertical incisions in the bark near the base of the trunk, then setting fire to the tree below the cuts, and having thus killed it, leaving it for a couple of years before collecting the exudation. The tree is killed in the hot season, and the gathering takes place in February-Mareh. In the Coimbatore district, the dammar is extracted from the tree by piling firewood to the height of 1 yd. around the base of the trunk, and lighting it. The resin subsequently exudes from the trunk as high as the flames reached. The operation is conducted at any season of the year, and the dammar continues to flow for 10 years between the months of April and November, and is collected in January. After yielding for 10-12 years, the tree decaya. The quantity of resin obtained is stated at 30-40 dungallies (say 150-200 lb.). It occurs in large stalactitic pieces, of bright black colour, when viewed from a distance, but trans lucent and deop reddish-brown when seen in thin laminae against the light. It ie quite homo geneous, and hae a vitreous fracture. It is insoluble in cold, but partially soluble in boiling alcohol on the addition of camphor. When powdered, it is readily soluble in turpentine-oil. By distillation, it yields about 78 per cent. of oil resembling rosin-oil. It is largely used in India in making bottling-wax, varnishes, &e., but in this country would hardly compete with common rosin.
Another species, C. bengalense, of Sylhet and the adjacent mountainous countries, jields a large quantity of pure, clear, amber-coloured resio, which soon becomes hard and brittle, and is not unlike copal, but lightly valued by tho nativea.
4. Rock Dammar.—Tbis is furnished by two species of Hopea, H. odorata of Rangoon, Pegu, Martaban, and Tenasserim, and H. micruntha of Malacca, Sumatra, Borneo, and Lahuan. The re,sin of the former occurs in nodules about the size of walnute, of a pale-atraw colour to colourleaa, brittle, with a shining resinoid fracture, scarcely distinguiehable in appearance from the com mercial E. Indian dammar (of D•rnunara orient,di6). It dissolves resdify in turpentine-spirit and benzol, forming a clear bright solution, drying rapidly and smoothly when applied as a varnish. In all essential qualities', it is quite equal to E. Indian dammar, and ia rather superior to it in hardness. The resin of H. micrantha is met with in pieces having the same size as the foregoing, but darker coloured and less friable. In other respects, there is no broad difference between the two kinds.