PLANTS PRODUCING GUMS AND RESINS 323 



In Europe first quality Madagascar copal is quoted at 4 francs 

 per kilo. 



Hymenaea Hornemannlana.- The synonym for this plant which, 

 according to Hayne, constitutes a distinct species, is Trachylobium 

 Honic)iiannianii7n. It is probably a variety of the Madagascar 

 Hymciiiva, and it produces the Zanzibar copal. 



As in the case of the other copal trees, considerable masses of resin 

 exude from the trunk and large branches. Captain Elton says that 

 the copal tree is tunnelled by numerous insects, and when they reach 

 the core the tree " seems to make an effort to check its destruction," 

 and resin is emitted in large quantities. 



In addition to the green copal, fossil copal is also found lying 

 in the rich organic top soil which covers the subsoil of compact blue 

 clay. The most important deposits are found on the coast, about 

 4' or s kilometres from the shore. On digging to the depth of a yard or 

 so the pieces of copal are found covered with red sand. 



These deposits are buried in a soil where copal trees were once 

 abundant. They have since disappeared and their place has been 

 taken by brushwood. 



Hymensea mossambicensis — It is thought that the Mozambique 

 copal, like that of Zanzibar, is probably only a form of Hymetiaea 

 verrucosa. 



In Mozambique this tree is tending to disappear, and at the present 

 day only fossil deposits are exploited. The chief of these occur in 

 the valleys where there must once have been huge forests of this plant. 

 These deposits are very badly worked by the negroes, who are satisfied 

 with extracting a few ounces of copal a day. 



In the Zanzibar and Mozambique trade three kinds of copal are 

 distinguished : Sandarusi za miti, or green copal ; Jackass, or semi- 

 fossil copal ; Sandarusi J or fossil copal. 



According to Hamerton, the quantity of copal exported from 

 Zanzibar is from 800,000 to 1,200,000 lb. per annum. 



Hymenaea Courbaril — A tree, from 25 to 30 metres high, of wide 

 occurrence in Brazil, the West Indies, Venezuela, Guiana, &c. 



It produces a resin known in commerce as semi-hard copal. The 

 most valuable is the semi-fossil variety which has been buried for a 

 more or less lengthy period and which arises from wounds or fissures 

 in the roots. The oxidized superficial layer has to be removed. This 

 resin melts between 180° and 200° C. 



The living tree exudes resin which, according to Paoli, is composed 

 of two kinds : one soluble in cold alcohol, the other only in boiling 

 alcohol. 



Heckel and Schlagdenhauffen have shown that the pericarp of the 

 fruit contains pockets which secrete a resinous product with which the 

 fruit is covered. 



According to de Cordemoy, the characters of this resin are as 

 follows : It is completely soluble in cold absolute alcohol. It is only 

 partially soluble in chloroform and ether. This writer concludes from 



