3i COMJIEKCIAL BOTANY. 



latter date it has been given tip by them, in consequence of 

 its having been found not durable when exposed to the air. 

 Articles mi^unfactured from it are said to have cracked on 

 the surface, and the inner portion to have lost its tenacity. 

 Balata seems to be unsuited for mixing vnth. gutta-percha, 

 and has, therefore, been generally used alone. At the 

 present time it is estimated that not more than fifty tons 

 are imported into this country annually, and that probably 

 another fifty tons go to France ajid the United States. 



As imported, balata, as a rule, is very uniform in 

 quality, fetching about 2s. per pound, while gutta-percha 

 ranges between Is. and 3s. 6d. per pound, according to 

 quality. 



GuTTA-SHEA (Butyrospermum Parkii). 



Under this name a substance has been brought to notice 

 duiing the past few years which resembles gutta-percha in 

 many respects, but is more brittle. It is obtained from shea 

 butter, the solid oil or fat expressed from the seeds of 

 Butyrospermum Parkii. The tree is a native of Western 

 Africa ; and the fat is not only used by the natives as 

 butter, but it has also been exported in considerable quanti- 

 ties to this country, since 1851, for soap-making. It is 

 estimated that the quantity annually imported from Sierra 

 Leone amounts to about 500 tons. It is used in this coun- 

 try only for hard soaps ; and in the course of manufacture 

 gutta-shea is found to be present to the extent of from -5 to 

 ■75 per cent. On the Continent it is largely used for 

 candle-making. In noticing this product, in the Kew 

 Report for 1878, Sir Joseph -Hooker says, " It is insoluble in 

 alcohol, a mixture of alcohol and ether, acids, and alkalies. 

 It is slightly soluble in piire ether, and ordinary animal and 

 vegetable oils and fat. From the extremely small propor- 

 tion in which it is present in shea butter, its extraction 

 would not be profitable ; and regarded as a bye-product it 



