lO J YEAR OF COST.l RICJN NATURAL HISTORY 



seasons except In places which lie in "precipitation shadows" 

 so to speak, like Cartago sheltered by Irazu. On the Pacific 

 side, on the contrary, there is often a well-defined division 

 of the year into a dry season ("verano") from December to 

 May and a wet season ("Invierno") from June to November, 

 the latter due to westerly winds bringing moisture from the 

 Pacific. 



These topographical and climatic conditions largely de- 

 termine the location and operation of Costa Rican railroads, 

 for with every rain the soil and rock — in many places loose 

 and friable — slide in large quantities down the slopes. The 

 erosion so produced has formed a vast number of valleys, 

 canons and channels of all sizes, whose positions, contours 

 and other characters are constantly changing. 



The capital of Costa Rica, San Jose, Is on the Pacific slope 

 at an altitude of 3800 feet (1160 meters). The construction 

 of a railroad connecting it with the Atlantic coast conse- 

 quently involved the crossing of the continental divide and 

 the traversing of the moist and ever-changing Atlantic slope. 

 As originally planned, this railroad was to run on the north 

 side of the volcanoes Turrialba and Irazu, crossing approxi- 

 mately at right angles the rivers which descend from these 

 peaks, ascend the pass of La Palma and so reach the Meseta 

 Central, or central plateau. In which San Jose lies. The 

 tracks were actually laid on this line from LImon to Carrillo 

 (1226 feet, 374 meters) at the north side of the pass, between 

 1872 and 1882, and communication between Carrillo and 

 San Jose was established by means of a carretera, or road 

 suitable for ox-carts, about twenty miles long. It was Im- 

 possible to maintain this line in operation, however. The 

 numerous rivers crossed by the road are subject to so many 

 violent floods that the stream-beds are constantly shifting 

 and railroad bridges were left high and dry over an empty 

 channel while the river flowed In an entirely nevfr bed. At 



