20 ANNUAL REPOKT SMITHSONIAN INSTITUTION, 1930 



NATIONAL ZOOLOGICAL PARK 



Animals added to the collection during the year numbered 759, 

 while 974 were removed through death, exchange, and return of ani- 

 mals, the collection standing at 1,996 at the close of the year. Owing 

 to lack of further housing facilities, it has been necessary to choose 

 very carefully in making additions to the collection, with the result 

 that the park now contains a great many rarities, including a number 

 of species not shown in any other American zoo. 



The total attendance at the park was estimated at 2,525,141, about 

 the same as in the preceding year. This total included 28,814 stu- 

 dents from 465 different schools. The value of the park as an educa- 

 tional institution, quite apart from its recreational value, is coming 

 to be more and more recognized. Here may be seen visitors of all 

 ages and all degrees of learning, from the j^oung child to the veteran 

 research M^orker and the advanced medical man, each of whom can 

 learn something of value concerning animals and animal life. 



Construction of the new reptile house authorized by Congress 

 was started in March, 1930. The best modern ideas as to the exhibi- 

 tion of reptiles will be incorporated in the building, which will per- 

 mit the National Zoo to show for the first time an adequate 

 representation of these interesting creatures. The next most ur- 

 gently needed building is one for small mammals, with which also 

 would be exhibited the great apes; these latter are at present shown 

 in inadequate cages where comparatively few people can see them 

 at a time. 



ASTROPHYSICAL OBSERVATORY 



The central station at Washington and the three observing sta- 

 tions on Mount Montezuma, Chile; Table Mountain, Calif.; and 

 Mount Brukkaros, South West Africa, have continued the exact 

 measurement of the intensity of the radiation of the sun as it is at 

 mean solar distance outside the earth's atmosphere. The values from 

 Mount Montezuma have continued to be satisfactory and are cabled 

 to Washington each day ; the values from Table Mountain are found 

 to be influenced by the haziness or humidity of the atmosphere, 

 and a new method of reduction to allow for these effects was being 

 developed at the close of the year, preliminary trials of which give 

 promising results. Reduction of Mount Brukkaros observations is 

 being postponed until this method is further tested for Table 

 Mountain. 



It has recently been discovered that a variation of large percentage 

 exists in the quantity of ozone at high levels above Table Mountain. 

 In order to make ozone corrections to solar constant values obtained 

 there from the year 1925 on, it became necessary to devise a method 



