285 



Consignments of this rubber, if well prepared, would be readily 

 saleable at satisfactory prices. 



Since the above was written a specimen of Mascarerihasia 

 elastica has been received from the Uganda and British East 

 Africa Exploration Syndicate, accompanied by a short note by 

 Mr. Henry Dalziel, who reports : " The enclosed specimens of 

 leaves, fruits, and wood are from a new kind of rubber tree, 

 lately discovered by the natives in Wanga District, British East 

 Africa, and called by them < Goa.' This tree is generally found on 

 the banks or near the sides of running streams where its roots 

 can get easy access to the water. The stems are from a few to 

 18 inches in diameter, and form a bole 20 feet high to where it 

 branches out. In old trees the bole has generally a great 

 number of hollows, with a rough scaly bark which can easily 

 be rubbed oft ; the inner bark is a quarter of an inch thick, and 

 easy to cut. When the tree is cut the latex oozes out very 

 slowly." 



A specimen of the wood of Mascarerihasia elastica from the 

 Wanga District, collected by Mr. H. Dalziel, is exhibited in Case 78, 

 Museum No. T. 



XLVI.-GUAYULE RUBBER. 



{Partheninm argentatum, A. Gray.) 



J. M. HlLLIER. 



Among the plants of economic value belonging to the natural 

 order Compositae none are more interesting than those known to 

 contain rubber or a substance analogous to rubber. During the 

 last decade considerable attention has been directed to two such 



plants of this order, viz : 



(Hy 



oxys sp.), a note on which appeared in Kew Bulletin, 1906, 

 No. 6, pp. 218, 219, and the Guayule of Mexico, the subject of the 

 present note. 



The first communication received at Kew on the subject of 

 Guayule was from the Mexican Land and Colonization Co., Ltd., 

 4, Moorgate Street, E.C., dated 29th December, 1902, requesting 

 information regarding the following extract from Circular No. 28 

 issued by the United States Department of Agriculture :— 



" An illustrative instance of the dangers likely to beset invest- 

 ments in rubber comes to hand as this Circular is being sent to 

 the printer. A well-known journal* notices a new substitute for 

 rubber, describing it as a gum obtained by grinding up the bark 

 and ' comparatively hard wood ' of a ' small scrubby bush and 

 then macerating in gasoline or other hydrocarbon solvent, By 

 this process the gum that comes out is chemically pure and 

 suitable at once for manufacture, and it forms a new composition 

 consisting of resin of the plant combined with a residual portion 

 of the hydrocarbon solvent.' The shrub, which has no milky 



29041 



Scientific American. 



C 2 



