312 COCOA CHAV. 



grows well here provided the layer of vegetable earth 

 is of sufficient depth. 



.Near the shore and the river-mouths salt soils occur. 

 If the salt water remains standing, the young cocoa 

 dies ; yet Chevalier saw near San Miguel a fine planta- 

 tion where the trees were often flooded by high tide. 

 This agrees with the experience, gained in Surinam, 

 that cocoa can stand a good deal of salt in the soil if 

 it has grown accustomed to it when young. 



As serious damage is done by sea winds the cocoa 

 trees have to be protected against them by thick shelter 

 belts of trees. 



The chemical composition of the soil in San Thome 

 is very variable. The analyses given by Chevalier yield 

 the following general figures : 



Per cent. 



Nitrogen . . . O07 to 0'2 

 Potash . . . 0-1 to 0-2 



Phosphoric acid . .0-07 to 0'5 

 Lime . . .03 



Organic constituents . 1 to 2 (in one case 7). 



The physical structure is to some extent shown by 

 the following figures : 



Per cent. 



Stones . . .15 



Gravel . . . .16 

 Fine Earth . . . . 68 to 90 



The following figures are also interesting : 



Per cent. 



Water . . . . 9 to 22 

 Humus . . . . 1| to 3 

 Sand . . ' . . . 40 to 50 

 Clay 30 to 50 



History. The first cocoa plants were introduced 

 into San Thome in 1822 from the island of Principe, 

 which had probably obtained them from the Spaniards 

 in Fernando Po. For a long time, however, the cultiva- 

 tion of cocoa made so little progress that as late as 

 1869 no more than 50 tons were annually exported, 

 but in the last quarter of the nineteenth century the 



