INTRODUCTION. 



Ixiii 



then crushed and shaken out. They make boots 

 of it which water cannot penetrate, and which, 

 when smoked, have the appearance of real leather. 

 Bottles are also made of it, to the necks of which 

 are fastened hollow reeds, so that the liquor con- 

 tained in them may be violently forced out by 

 pressure. One of these filled with water is al- 

 ways presented to each of the guests at their 

 entertainments, w^ho never fails to make use of 

 it by forcing the water into his mouth before 

 eating. Hence the tree which produces the gum 

 is sometimes called the Syringe-tree. Caout- 

 chouc is soluble in ether, and in the essential oils 

 of turpentine and lavender ; and even, if boiled 

 for a quarter of an hour in w^ater, it may be so 

 far dissolved, that the edges will finnly unite. 

 If a bottle be soaked in sulphuric ether until 

 quite soft, it may be inflated until it becomes so 

 thin as to be transparent, and sufficiently light 

 to ascend when filled with hydrogen gas. Water- 

 proof cloth is manufactured in Europe by dis- 

 solving it in the oil distilled from gas-tar, and 

 spreading the mixture on the surface of a piece 

 of cloth, upon which a similar piece is then ex- 

 tended, and the whole passed between a pair of 

 rollers. The largest India-rubber trees grow on 

 the banks of the river Amazon, where they attain 

 a great height, being at the same time perfectly 

 straight, and bearing no branches except at the 

 top, which is but small, covering no more than 

 a circumference of ten feet. The leaves are 

 large, tough, and leathery, green above, and 

 whitish beneath. The seeds contain a thick oil, 

 which answers the purpose of butter in the 

 cookery of the country. The fragrant aromatic 



