Costa rica, the most southern of the states of Central America, lies between eight and eleven degrees of north latitude, and presents great inequalities of surface. Its length is traversed from northwest to southeast by the range of the Cordilleras, which rise in their highest point, the Pico Blanco, in the southern part of the republic, to an elevation of feet. In the middle of the country the range forms the western border of a plateau whose elevation is about 5000 feet, and whose eastern rim is marked by a chain of volcanoes. The principal rivers of the country, which ﬂow into both oceans, take their rise in this plateau. Here also the more important part of the population dwells, in the two towns of San José and Cartago. The climates of the eastern and western regions present material differences. The eastern slope of the country receives the trade-winds loaded with the moisture and clouds derived from the evaporation of the Caribbean Sea under a tropical sun. Constant rain falls on the mountain sides, and the rivers ﬂowing into the Caribbean Sea are remarkable for the volume of water they contain as compared with the length of their courses. The climate of the country west of the mountains is much drier, but not so much so as to constitute aridity. The entire republic, but especially the eastern region, is covered with a dense tropical vegetation.