REPORT OF THE SECRETARY. 27 



The opportunities for securing animals to bring back were found 

 to be in some respects less favorable than had been anticipated, but 

 fortunately the zoological garden at Pretoria was fairly well stocked, 

 and the director was kind enough to deplete the collection somewhat 

 for the benefit of his distant colleagues. Most of the animals which 

 Mr. Loring brought back were obtained there, an interesting collec- 

 tion of mammals and birds being secured. The mammals obtained 

 include a gemsbuck, a blessbuck, a white-tailed gnu, a nilgai, four 

 springbucks, a pair of duikers, a pair of meerkats, and a few mon- 

 keys and rodents. Among the birds are two secretary vultures, a 

 bateleur eagle, a hornbill, francolins of several species, a few 

 touracous and hawks, and a number of smaller birds. The collection 

 has been divided between the three institutions concerned, accord- 

 ing to their choice, and in proportion to the share of the expenses 

 that was borne by each. Altogether there were secured 28 mammals, 

 representing 13 species; 60 birds, of 25 species; and 55 snakes and 

 tortoises, of 8 species. 



While in South Africa, Mr. Loring visited and made notes on the 

 zoological gardens at Cape Town, Durban, Bloemfontein, Johannes- 

 burg, and Pretoria. 



ASTROPHYSICAL OBSERVATORY. 



Measurements of solar radiation were continued as usual on Mount 

 Wilson. As stated in connection with the Hodgkins fund, an allot- 

 ment has been made to undertake similar work- in South America. 

 Much attention was devoted by Director Abbot to the preparation 

 of the equipment of this expedition. Valuable new instruments 

 were devised and constructed under his direction. Owing to war 

 conditions the expedition was located temporarily at Hump Moun- 

 tain, X. C, in May, 1917, and shelters prepared and apparatus 

 set up and adjusted under the care of Messrs. Abbot and Aldrich. 

 The research on the absorption of terrestrial radiation by vapors 

 of the atmosphere, upon which Mr. Fowle has been engaged for 

 several years, has been completed, and the results, which are of 

 great importance to meteorolog^v, have been made ready for pub- 

 lication by the Institution. A paper of uncommon interest, by PL 

 Helm Clayton, based upon observations bv the Astrophysical Ob- 

 servatory, has been published in the Smithsonian Miscellaneous Col- 

 lections. The author shows that the short-interval solar variations, 

 discovered in Mount Wilson work, affect terrestrial temperatures 

 and pressures the world over in a well-marked and predictable 

 manner. It is greatly to be hoped that daily solar-radiation obser- 

 vations at all times of the year may be obtained for use in such 

 meteorological researches. It was for this purpose that the South 



