246 POPULAR ECONOMIC BOTANY. 



pieces, variable in size, opake, and generally of a light 

 sherry-brown colour. It has been conjectured that a species 

 of Mesembryanthemum yields this gum, but most probably 

 this is an error; we are however totally ignorant of its 

 origin. It is only an occasional import. 



The Gum-resins and Eesins used in the arts are not very 

 numerous, and one of them (Dragon's Blood) has already 

 been described in the previous chapter; the principal 

 are — 



Copal, which is of various kinds, yielded by different 

 trees in Africa and South America, the East Indies, and 

 Australia. 



Brazilian Copal is produced by plants of the Natural 

 Order Leguminosce, chiefly by some species of Hymenaa, 

 and by Trachylobium Martianum. It is in large angular 

 pieces, often as large as a hen's egg, very transparent, and 

 of a light yellow colour. 



African Copal is also in large fragments of rounded tears, 

 or masses; it is darker in colour than that from Brazil, and 

 less transparent, often having a reddish-yellow colour and 

 dusty surface. It is supposed to be produced from a species 

 of Hymenaa ; but there are evidently different sorts of 

 African Copal. 



