8 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1942 



change Service was discontinued for the duration at the request of 

 the Office of Censorship. 



National Zoological Park. — Although war conditions reduced the 

 number of out-of-town visitors to the Zoo, more people from nearby 

 areas came by bus and streetcar and on foot, bringing the total at- 

 tendance for the year to 2,523,300, or sightly more than the number 

 for the previous year, A considerable proportion of the attendance 

 was made up of men in the armed services, many of them enjoying 

 their first oportunity of visiting a large zoo. As usual, a large num- 

 ber of gifts of animals came to the Park, and there were 65 mammals 

 born, 40 birds hatched, and 2 reptiles born during the year. Deaths 

 included a sulphur-crested cockatoo that had been in the Zoo for 52 

 years, and the American bald eagle "Jerry," a Zoo resident for 26 

 years. The epidemic of psittacosis that caused serious losses of 

 birds and caused the closing of the bird house to the public for 3 

 months, as noted in last year's report, was finally subdued through 

 the cooperation of the United States Public Health Service and the 

 District of Columbia Health Department. Many of the poisonous 

 reptiles have been removed from the Zoo, leaving so few that they 

 could be quickly disposed of in an emergency. At the close of the 

 year, the collection contained a total of 2,411 animals, representing 

 722 different species. 



Astrophysical Ohservatory. — The most important event of the 

 year was the publication of volume 6 of the Annals of the Observa- 

 tory, which covers its operations from 1920 to 1939. Besides de- 

 scribing in detail the principal research on the variation of the sun's 

 radiation, the volume is the culmination of several years' work de- 

 voted to revising the daily results of observation of the solar con- 

 stant of radiation at the three field observing stations at Montezuma, 

 Chile, Table Mountain, Calif., and Mount St. Katherine, Egypt, 

 from 1923 to 1939. The values published clearly indicate the vari- 

 ation of the sun between extreme ranges up to about 3 percent for 

 the period covered. The variation is shown to be composed of 14 

 periodicities ranging from 8 months to 273 months. Each of these 

 periods is reflected in terrestrial temperature and precipitation as 

 recorded by official weather services. Another important event was 

 the incorporation as a branch of the Observatory of the Smithson- 

 ian Division of Radiation and Organisms, hitherto supported by 

 private funds. Considerable confidential work for military purposes 

 was done in the Observatory's instrument shop under the care of 

 the Director. Because of the discovery that the percentage varia- 

 tions of the intensity of sun's rays is 6 times as great for ultraviolet 

 rays as for the total of all wave lengths, apparatus was prepared in 

 the instrument shop for restricting the determinations of solar varia- 

 tions to the spectral regions of the green, blue, violet, and ultraviolet 



