262 ECONOMIC BOTANY. 



described by La Condamiue in 1751. It was employed for 

 a long time simply to erase lead-pencil marks, a use £rst 

 pointed out by Magellan. When the process of vulcan- 

 izing the Caoutchouc was invented — which consists of im*- 

 pregnating a small quantity of sulphur with it, which has 

 the effect of -hardening it, and extending its elasticity' to 

 wider limits of temperature — its uses were greatly multiplied, 

 and now it is in the arts one of the most important of all 

 vegetable products. It was, therefore, sought for in other 

 plants than. those from which it was obtained by the Indians. 

 It is now obtained from Siphonia braeiliensis (family £vr 

 phorbiacem), in Brazil ; Urceola elastica (family Apocynaeem), 

 in East India; Ficus elastica (family Urticacece), in East 

 India ; Vahea gummifera (family Apocynacece), in Mada- 

 gascar. A very small quantity is collected from swamps, 

 which has spontaneously exuded and hardened. It is mostly 

 obtained by making incisions into the trees. A horizontal 

 incision is made, and from this upwards a vertical incision 

 and many oblique ones are made. The juice then flows 

 out, and is collected in earthen vessels, or wooden ones 

 lifled with clay. It is worked at once, ammonia being added 

 to prevent its coagulation. A fire is built with the fruits of 

 a Palm (4tefea funifera'), and over it are held wooden 

 paddles, or earthen forms, previously dipped in the milky 

 juice; when the liquid is evaporated, a thin dark-colored 

 layer of Caoutchouc is found deposited, and the process is 

 repeated very many times till a thick coating of Caoutchouc 

 is formed. Then the earthen form is broken, or the 

 Caoutchouc is cut down on one side and removed from the 

 paddle, and in this form is exported. Another method in 

 some places is followed, which is as follows : The liquid is 

 diluted with four times its volume of water, and stirred. 



