Page:Popular Science Monthly Volume 67.djvu/242

236 of many tropical uplands. Thanks to the researches of Pettenkofer, Voit, 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 José. 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 José. The Boletin is published by the government meteorological observatory, an institution founded in 1889 by that remarkable Costa Rican, 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.