CLIMATE OF CENTRAL AMERICAN PLATEAU. 231 



THE CLIMATE OF THE CENTRAL AMERICAN 



PLATEAU. 



By gustave MICHAUD, D.Sc, 



SPRINGFIELD, MASS 



A FEW weeks ago the Springfield Republican published the fol- 



-*--^- lowing extract from a letter sent by our minister to Costa 



Rica, Hon. W. L. Merry, to Gen. G. W. Davis, governor of the Panama 



canal zone : 



Six years and a half of residing in San Jos6 have made manifest to me 

 its fine and agreeable climate. When this fact will be known to the many 

 American officials and employees coming to the Isthmus of Panama to work 

 under the canal commission, they will take advantage of the opportunity to 

 visit Costa Rica for recreation and for their health. ... A few weeks stay 

 here would invigorate our men. 



The writer spent six years, from 1889 to 1895, on the Central 

 xAmerican plateau and gathered some meteorological and physiological 

 data which led him to the conviction that our minister's statement is 

 not exaggerated. The climate of that portion of the upland which 

 extends from the Panama isthmus to the Yucatan peninsula, and 

 which includes the highlands of Costa Rica, Nicaragua, Honduras and 

 San Salvador, has features of its own, not frequently found under the 

 tropics and never outside of them. 



The uniformity of temperature throughout the year, which char- 

 acterizes the tropical climate, an altitude of some 1,000 feet above sea- 

 level, with its corresponding decrease in the density of air, a lower 

 temperature than could be expected for such an altitude in the torrid 

 zone, are the main features of the climate of the Central American 

 plateau. The last of these is the most important. The value of 

 tropical plateaus as health resorts is a subject which has been much 

 discussed recently. That of the Central American upland will be 

 better understood if some of the conclusions which have been reached 

 within the last ten years, as well as some of the experiments which 

 have led to these conclusions, are previously stated. 



The density of air decreases rapidly as one rises on a mountain 

 slope. At an altitude of 18,500 feet, a given volume of air contains 

 but one half the quantity of oxygen which it contains at sea-level. 

 Scarcity of oxygen does not seem to be a desirable condition, yet re- 

 cent experiments have shown that, within certain limits, that very 

 quality of mountain air induces in the human system changes which 



