452 VEGETABLE SUBSTANCES. 



afford a much larger quantity of camphor when the 

 sap has been suffered to pass to the concrete state by 

 several months' drying. 



This substance was very early known to the eastern 

 nations, and was introduced into Europe by the 

 Arabians. 



INDIA-RUBBER, OR CAOUTCHOUC. 



The substance called Indian Rubber, or Caoutchouc, 

 was not known in Europe until the beginning- of the 

 1 8th century. It was then brought as a great curiosity 

 from South America. It usually appeared in this 

 country in the shape of bottles, birds, or other fan- 

 tastically moulded forms ; and nothing could be learnt 

 of its nature, or of the manner of obtaining it, except 

 that it was of vegetable production. Europeans 

 continued in this ignorance of its origin until a 

 deputation tof the French Academicians undertook a 

 voyage to South America in 1735, for the purpose of 

 obtaining the correct admeasurement of a degree of 

 the meridian. These philosophers did not confine 

 their attention to the one great object of their pursuit, 

 but likewise enriched the scientific world by ascer- 

 taining many facts connected with natural history, 

 and which had heretofore been hidden in obscurity. 

 Among these subjects the manner in which that 

 peculiar substance, caoutchouc, was produced, became 

 an object of inquiry. These academicians discovered 

 at Esmeraldas, in Brazil, trees called by the natives 

 tee, whence flowed a milky juice, which, when dried, 

 proved to be what is called India-rubber, or caoutchouc. 

 The heve was likewise recognized as growing in 

 Cayenne and on the banks of the Amazon river. It 

 has since been discovered that caoutchouc may likewise 

 be obtained from another species of tree growing in 

 South America tliejatropha elastica. 

 If these trees are punctured, a milky juice flows 



