48 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1933 



observations cannot yet be determined. As soon as the revision of 

 the method of reduction of observations from Montezuma, Chile, 

 now in progress, is completed, it will be possible to decide. 



Having found the variation of the sun so obviously periodic in 

 character. Dr. Abbot and Mrs. Bond spent a great deal of time on the 

 study of the departures from normal temperature of Bismarck, N.Dak. 

 This station was chosen as one with a long record, published in World 

 Weather Records, and situated in a region subject to the most direct 

 influence of the sun without near-by interference of oceanic and moun- 

 tain climates. The data have been studied for the interval 1875 to 

 1925 with a view to determining therefrom whatever periodicities 

 might be contained. It is hoped that, based upon this analysis, a 

 prediction might be made of the march of departures from normal 

 temperature at Bismarck for the period 1925 to the present which 

 could be immediately compared with observation so as to see if such 

 prediction would be verified. The study is not yet completed but 

 indicates clearly that the seven periodicities found in solar variation 

 are of importance in the control of the temperature at Bismarck, 

 although for reasons not fully understood changes of phase and 

 amplitude confuse effects. A hopeful line of study of the causes of 

 these changes of phase and amplitude is in progress. 



Mr. Aldrich, besides attending to the routine of the observatory 

 and the demands of the field stations in California, Chile, and Egypt, 

 has reconstructed the delicate parts of the double-barreled water- 

 flow pyrheliometer, has taken part in the preparation of an exhibit 

 for the Century of Progress Exposition in Chicago, and has under- 

 taken the revision of the method of reduction of the observations at 

 Montezuma. 



Mr. Fowle's work has been largely confined to the preparation of 

 the eighth edition of the Smithsonian Physical Tables. 



The instrument maker, Mr. Kramer, has had under construction 

 apparatus for the continuation of the study of the solar spectrum at 

 great w^ave lengths, to be noticed below, as well as the rebuilding of 

 certain apparatus used by the stations at Table Mountain, Monte- 

 zuma, and Mount St. Katherine. 



MOUNT ST. KATHERINE EXPEDITION 



Financed by the generosity of Mr. John A. Roebling, an expedition 

 under the charge of Harlan H. Zodtner, assisted by Frederick A. 

 Greeley, was prepared and dispatched to occupy Mount St. Katherine 

 near Mount Sinai in Egypt. The expedition went forward in March 

 1933. Arrangements had been made with the Convent of Mount 

 Sinai to construct trails, protect the springs from pollution, and 

 prepare the buildings for observing and quarters for the observers 

 at the summit of Mount St. Katherine. A recent report indicates 

 that the preparations are far advanced. 



