TESTIMONY ON CLIMATE. 43 



not from another might mean merely that the former had access to a 

 larger supply of water and was thus able to maintain a greater latex 

 pressure. Such questions will need to be studied in detail after 

 uniform methods of tapping and pressure measurement have been 

 devised. This need not obscure the fact that, unless tapping be done 

 at the most favorable date, the productiveness of rubber trees and the 

 localities in which they grow may be misjudged very easily. 



CASTILLA IN NICARAGUA. 



The opinion that the production of rubber by Castilla is favored by 

 a dry season is based, as yet, only on observations made in Guatemala 

 and southern Mexico; other conditions and different species of Cas- 

 tilla may be found in the countries to the southward. Moreover, it 

 is scarcely reasonable to expect the interested public to adopt what 

 may appear to be a radical view of Castilla culture without understand- 

 ing the basis of the current opinion that continuously humid regions 

 are required for the production of rubber. 



The Report on the Caoutchouc of Commerce, written by James 

 Collins, and published in 1872 under the auspices of the British Gov- 

 ernment, remained for many years the most complete and authorita- 

 tive statement of the subject. It was very frequently quoted by 

 subsequent writers, and has probably done most to establish the idea 

 that continuous humidity is required by Castilla. Collins says: 



The species of Castilloa seem to like best and thrive in thick, humid, warm forests. 

 They abound in Nicaragua; and as I have, through the kindness of my friend Dr. 

 Bureau, of Paris, received from M. Paul Levy, a botanical collector in Nicaragua, a 

 good account of their history there, it will serve to give a correct idea of their habits. 



The basin of the Rio San Juan is where the ule tree grows to perfection. This 

 river is the natural vent of the two vast basins of the lakes of Nicaragua and Mana- 

 gua, receiving numerous tributaries, which have all their sources in the innumerable 

 tracts hitherto virgin and unfrequented, and where the trees abound. The ground 

 is very fertile. The district is very unhealthy ; it rains for eight or nine months in 

 the year, and the climate is very warm and humid. The trees prefer humid and 

 warm soils, but not marshy, clayey, or gravelly ground, and the presence of these 

 trees is looked upon as an indication of a fertile soil. . . . The ule is often near 

 water-courses, and nearly always on the banks. a 



CASTILLA IN COSTA RICA. 



The most extensive recent publication on Castilla is by Herr Th. F. 

 Koschny, a resident of Costa Rica, whose opinions on the subject of 

 climate appear to be nearly opposite to those stated above. He says: 



The safest and most productive rubber plant is the Castilloa elastica of Central 

 America. Its tenacity of life and adaptability to soil and climate are seldom 

 exceeded by other trees; the same is also true of the quantity and quality of the 

 rubber. 



It requires a humid, warm climate, and with respect to rainfall less depends upon 

 the amount of precipitation than upon the distribution of it. The shorter the dry 

 - 9 



« Collins' s Report on Caoutchouc, p. 14. 



