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POPULAR SCIENCE MONTHLY 



of many tropical uplands. Thanks to the researches of Pettenkofer, 

 Yoit, and especially to the heliotropic experiments carried on a large 

 scale by Finsen at the Light Institute of Copenhagen, we begin to 

 realize that the chemical rays of sunlight have as much to do with 

 nerve action and metabolism as with sunburn. So far as the latter 

 phenomenon is concerned, the worst sunburn the writer ever saw . . . 

 and felt . . . was got through a colored shirt, in the neighborhood of 

 the city of San Jose. About 8,000 or 10,000 feet, it is impossible not 

 to notice the extraordinary intensity of solar illumination when the 

 sun is nearing the zenith. At a much lower altitude, in the case of 

 such subjects as ' Noon at the village market,' the photographer soon 

 learns that times of exposure which gave the best results in the United 

 States give overexposed negatives on the Central American plateau. 



From one of the scientific periodicals published in the progressive 

 little republic of Costa Rica, El Boletin del Instituto Fisico-Geografico, 

 the writer compiled the following summary of the climatic conditions 

 of the city of San Jose. The Boletin is published by the government 

 meteorological observatory, an institution founded in 1889 by that re- 

 markable Costa Eican, Don Mauro Fernandez, who was then Minister 

 of Public Instruction. The observatory has a staff of four scientists 

 and has rendered considerable service to the study of the climatology 

 of that quarter of the world. The data represents the average of 

 observations extending over a period of twelve years. 



