378 Un&ia*1Rubl)er Culture in 



deavored to obtain all the data possible on the subject, so as to supply 

 by the experience of others and my own limited observation what I 

 could find nowhere else. The result of my investigations was not as 

 complete as I could wish, owing to the fact that the rubber-tree not 

 having been cultivated in those localities, no experiments as to its de- 

 velopment had been made; and, consequently, there are only con- 

 jectures, more or less well founded, concerning it. The summing up 

 of some probable conjectures on this subject is what I shall endeavor 

 to record in this paper. 



II. 



DESCRIPTION OF THE RUBBER-TREEBOTANICAL NAME CHEMI- 

 CAL ANALYSIS SPECIFIC GRAVITY OF RUBBER WHEN RUBBER 

 WAS FIRST USED VULCANIZED RUBBER. 



The tree that produces rubber belongs to the family of Euphorbiacea 

 trees, shrubs, and grass that gives a milky juice. This family is com- 

 posed of more than fifteen hundred species, which grow principally in 

 intertropical regions. 



Its botanical name is Jatropha elastica, 1 according to Linnaeus; 

 Siphonia elastica, according to Persoon; Siphonia cahuchu, according 

 to Screber and Wildenow; Haevea guianensis, according to Aublet; and 

 Echites corymbosa, according to Jacquieu. The trees called Cecropia, 

 Peltada, Ficus religiosa, and Indica produce a substance similar to rub- 

 ber, but inferior to it. The Asiatic rubber-tree called Ficus and Urceola 

 elastica^ grows to a greater size than the American, but its product is 

 inferior in quality to that of the latter. 



M. de la Condamine, describing the rubber-trees on the banks of 

 the Amazon River, says that they grow rapidly, are perfectly straight, 

 have branches only near the top, and cover a surface of not more 

 than ten feet. 



They have three seeds contained in a pod with three cells, in each 

 of which there is a kernel which, boiled in water, produces an oil that 

 is used like butter. 



1 1 find in the Treasury of Botany, edited by John Lindley, and published in 

 London in 1870, that there are four species of India-rubber: first, Ficus elastica; 

 second, Siphonia elastica, which is the one prevailing in Brazil ; third, Castilloa elas- 

 tica, which is the one raised in Soconusco ; and fourth, Unceola elastica. The Cas- 

 tilloa elastica is described as a Mexican tree pertaining to the Artocarpacea, which has 

 masculine and feminine flowers on the same branch. The masculine flowers have 

 several stems inserted in a semi-spherical perianth, the feminine flowerS consisting in 

 several ovaries contained in a cup. 



All the India-rubber trees that I have seen in the United States are entirely differ- 

 ent from those which grow in Mexico, and I think that they belong to the Siphonia 

 elastica family. 



