PREFACE. 



In the year 1902 the United States imported coffee to the value of 

 $70,982,155, sugar $55,061,097, and crude rubber $24,899,230. The 

 imports of crude rubber for the last five years were valued as follows : 



1898 $25,386,010 



1899 31,707,630 



1900 31,376,867 



1901 28,455,383 



1902 24, 899, 230 



Total 141,825,120 



Average 28, 365, 024 



After sugar and coffee, crude rubber is the largest of the tropical 

 imports of the United States, and it is the only one of these three for 

 which we are still entirely dependent on foreign countries. Rubber 

 culture is also the tropical industry in which the largest foreign invest- 

 ment of American capital has been made, and this is far larger than 

 that of any other country. 



The present paper on "The Culture of the Central American Rubber 

 Tree" is the result of a preliminary study of rubber culture in Guate- 

 mala and Southern Mexico by Mr. O. F. Cook, Botanist in Charge 

 of Investigations in Tropical Agriculture, who has already left for a 

 second visit to Central America and Mexico, during which further 

 attention will be devoted to the same subject. 



These studies are directed primarily to the question whether rub- 

 ber culture is promising for Porto Rico and the Philippines, and the 

 principal fact established in this report, that a continuously humid 

 climate is neither essential nor even desirable for rubber culture, 

 promises well for the extension of this industry to the tropical islands 

 of the United States. As a basis of effort in this direction the more 

 important results of the experiments which have been made with the 

 Para and other rubber trees in the East Indies and elsewhere have 

 been brought together, with explanations of their possible bearing 

 upon the culture of the Central American rubber tree. 



The paper will have, however, a more immediate and popular inter- 

 est in connection with the subject of investments in rubber culture, 



« Not including imports from Hawaii and Porto Rico. 



