SOLAR RADIATION.

Washington, D.C.: GPO Magazine. Very Good. Soft cover. pp107-120, plus three plates. Removed from ANNUAL REPORT OF THE BOARD OF REGENTS OF THE SMITHSONIAN INSTITUTION, FOR THE YEAR ENDING JUNE 30, 1932. In plastic report covers. VG. From the article: "Directly or indirectly our most important interests depend on the solar radiation. The sun rays keep the earth warm enough to sustain life. Variations of their intensity associated with summer and winter, and with light and day, produce climates. Slight variations of the original output of rays from the sun itself seem to be highly influential in altering the weather. All growth in plants depends upon the application of solar energy. Our atmosphere is the source of carbon, which is a principal plant constituent. The trifling percentage of carbonic acid gas contained in air is the essential food of plants, but it can not nourish them without the help of radiation. The health of animals, including man, requires radiation. The prevention of rickets by the curious direct and indirect influences of ultra-violet rays has formed a fascinating chapter in the story of recent investigations.".