Loango copal occure in broken sticks whose natural length must amount to several spans. Ac e,ording to the eulour, two kinds are disting-uished, a white and a red. The former consists of colourless or white to yellowish grains; the latter, of reddish ur brownish grains or fragtnents. The red copll of Loango is preferred to the white, on account of superior hardness, transparency, and homogeneity. Its sp. gr. is 1.064. The fracture is conchoidal and glistening, and the scratch-line is free from splinter. The powdor does not adhere to the teeth.
Angola copal forms globular, rarely flattened pieces. The former are 1-21 in. diam., while occasionally lumps as large as a child's head, and weighing 3-4 lb., are unearthed. The natural pieces are coated with an earthy, dirty-white to brown ei list, which is often facetted like the surface of Zanzibar copal. But the excrescences on Angola copal are much larger than on any E. African copal, their length reaching 0.15-0.45 in. Homogeneous pieces are rare. The grains and sticks are mostly cracked, penetrated by air-bubbles, and contain fragments of bark. This copal is partly colourless, partly yellowish, reddish, or brownish. The colourless or slightly coloured are dull ; the strongly coloured aro bright, transparent, and homogeneous. The latter have consequently a higher price. On fresh surfaces, the scratch-line is smooth ; on older, somewhat splintery. The sp. gr. lies between 1.062 and 1.081 Hatschett stetee that some copal is soluble in hot alkaline leys, but Filhol says that E. Indian (which may be Zanzibar or Manilla) is not soluble even after some hours. According to Berzelius, several copals are soluble in spirit of wine on the addition of camphor. Cloez says that copal (kind not specified) is largely soluble in chloroform, slightly in absolute alcohol. Draper names cajuput oil as a good eulvent. Copal (kind not stated) is insoluble in linseed-oil, but soluble in castor-oil, the solutiun mixing with epirit of wine, but, separating on standing. Violette states that Calcutta copal ie soluble in linseed- and turpentine-oils, when previously heated at 350°-400° (662°-752° F.) in a closed vessel, and that the solution gives a fine varnish. Filhol remarks that the proportion of carbon diminishes in powdered copals by long keeping, and that such then become e,ompletely soluble in alcohol, ether, and turpentine-uil. (See also Varnish.) The hardness of the copals is one of their most characteristic features, and its degree is the principal consideration in estimating their commercial value, increasing in the same proportion. All copals are scratched by calc-spar ; but all, with the exception of the S. American (Jutahy-seca) scratch talc. The hardest copals are those whose hardness lies between that of crystallized copper
sulphate and rock-salt, softer than the latter, harder than the former ; to these, belong Zanzibar and Mozambique cupals. The hardness of the copals of Sierra Leone, Gaboon, and Angola resembles that of rock-salt. Softer are those of Benguela, New Zealand (Kauri), and Manilla (Dammar), while softest of all is S. American (Julahy-aca). The sp. gr. of the copals varies considerably, according to the amount of air inclosed in the cavities. This variation is shown in the annexed table :— It thus appears that the sp..gr. of a copal is in inverse proportion to its value ; and that while the soft inferior copals contain much air, the hard valuable ones have less.
The London market values of the copals are approximately as follows :—Zanzibar (called " animi"): fine washed, 14-23/. a cwt.; good, 12-19/. ; sorts and small, 9-16/. ; pickings, eze., 4-12/. Copal : Angola, red, 3-7/. a cwt. ; Benguela, 3/.-3/. 10s. ; Sierra Leone, 7i-10d. a lb.
For the other so-called copals, see as follows :—Dammar, p. 1644 ; Piney, p. 1678 ; Jutahy seca, p. 1666 ; Kauri, p. 1666.
Dammar, Damar, or Dammer (FR., Dammar ; GER., Dammar).—The name " dammar " is applied genetically to a number of resins having similar properties, and distinguished by specific prefixes. They will be described here in the following order :—(1) Dammar proper, or E. Indian dammar ; (2) Sal dammar ; (3) Black dammar ; (4) Rock dammar.
1. E. Indian Dammar.—This product, which is also known as " Singapore" or " white" darnmar, is obtained from the gigantic Amboyna pine (Dammara orientalis), a native of Malacca, Borneo, Java, Sumatra, and the Moluccas, growing in the hilly country, and also cultivated to some extent in Java. The main supply of the resin is furnished by Amboyna. Immediately above the root of the tree, occur numerous excrescences, sometimes as large as a man's head, whence exudes an agglutinative liquid that solidifies after some days into elongated masses of resin. In Sumatra, the natural exudation is so abundant that no trouble i8 taken to make incisions in the trees. In other places, the supply is increased by raaking incisions on the lower portion of the trunk, and placing small receptacles for the collection of the resin. The dammar which exudes from the upper portion of the trunk forms large stalactites, at first vitreous and colourless, but gradually becoming golden-yellow, which are detached at intervals. In the dense mountain forests of Sumatra, huge pieces of dammar fall from the trees and get washed into the rivers, whence they are collected by the natives.