EEPOET OF THE SECRETAEY. 33 



the erection of buildings for the animals in the park since its estab- 

 lishment. The wooden structures which originally sheltered the 

 animals could therefore be replaced only as strict economy in admin- 

 istration expenses permitted. As the appropriations for adminis- 

 tration for a number of years have been but little more than sufficient 

 to maintain the park, it can not now be said how soon the |)lans for 

 the new building may be carried into effect. • There is also needed a 

 new aquarium building, since the present structure, originally built 

 in the most temporary manner for use as a hay shed, is fast falling 

 into decay, and a general aviary, antelope house, inclosures for sea 

 lions and seals, and a centrally located office building are much 

 desired. 



Under the special appropriation allowed for the reconstruction and 

 repairing of walks and roadways the most notable improvements of 

 the year have been made, several long concrete approaches having 

 been constructed, and a considerable portion of roadbed having been 

 remade. As in previous years, particular attention has been devoted 

 to preserving the natural beauty of the grounds. 



During the year there were 591 accessions, which included 68 gifts, 

 91 births, 397 purchases, and 32 exchanges. There were 382 losses, 

 by death, exchange, and return of animals. Total number June 30, 

 1908, 1,402. 



ASTEOPHYSICAL OBSEKVATORY. 



The work of the Astrophysical Observatory during the last fiscal 

 year has consisted (1) of solar observations on Mount Wilson, Cali- 

 fornia, and at Washington, (2) a solar eclipse expedition to Flint 

 Island in the southern Pacific, and (3) the final preparation and pub- 

 lication of the second volume of the Annals of the Observatory. 



The Mount Wilson observations, continued from the summers of 

 1905 and 1906, were directed toward securing as many records of 

 intensity of solar radiation as possible for the study of solar changes. 

 As in former years, other kinds of measurements were made, notably 

 on the brightness of the sky and on the reflection of the clouds. 

 Since the observations as a whole have shown that the variation of 

 solar radiation is highly probable, and since numerous days suitable 

 for solar radiation measurements were found in the months from 

 May to November on Mount Wilson, it is proposed to erect, on a 

 small and well-isolated plot of ground leased for the purpose, a fire- 

 proof observing shelter to be occupied by Smithsonian observers each 

 year during the months mentioned. This will enable frequent obser- 

 vation of the " solar constant " during a period of years at least equal 

 to the sun-spot cycle, a research regarded as of great importance by 

 the late director, Mr. Langley. The work at Washington included 

 the observation, with improved methods, of the relative brightness of 



