REPORT OF THE PRESIDENT, 1905. 25 



to be nearly if not quite complete by the end of another year. 

 Through the courtesy of the University of Chicago, the Snow tel- 

 escope of the Yerkes Observatory has been mounted and been in con- 

 stant use at the Solar Observatory during the past summer. This 

 3-foot reflecting telescope has already furnished excellent results and 

 justifies the sanguine expectations entertained with regard to the 

 5-foot reflector now Hearing completion. The unusually favorable 

 atmospheric conditions which prevail day and night at the site of the 

 observatory have attracted the attention of astronomers and astro- 

 physicists generally. During the past summer a party under the 

 direction of Prof. S. P. L,angley, Secretary of the Smithsonian Insti- 

 tution, has been there observing data for the solar constant ; while 

 Prof. E. E. Barnard, of the University of Chicago, has utilized the 

 peculiar facilities of the site by installing the Bruce telescope of the 

 Yerkes Observatory and extending his remarkable photographic 

 charts of the Milky Way. 



Not very remotely allied to the work of the Solar Observatory is 

 the work of the Department of Terrestrial Magnetism, though the 



utility of the latter is perhaps more apparent than 

 restrial "Magnetism! tne utility of the former. All of the sciences, how- 

 ever, like the phenomena of nature, are more or 

 less interrelated, and this is especially the case with solar and terres- 

 trial physics. There is no doubt, at any rate, that solar activity and 

 terrestrial magnetism are in some degree related. Since the publi- 

 cation of the investigations on terrestrial magnetism by the illustrious 

 Gauss, during the first half of the nineteenth century, comparatively 

 little progress has been made in either theory or practice until within 

 the past decade. It is but just to remark that the recent fruitful 

 renewal of activity in this line of work is due chiefly to the enterprise 

 and energy of Dr. L,. A. Bauer, in charge of the Department of Ter- 

 restrial Magnetism. The execution of the plan he has outlined for 

 a magnetic survey of the oceanic areas, as well as of the land areas, 

 can not fail to secure data of signal value alike to marine transportation 

 and to magnetic theory. By means of specially devised instruments 

 and apparatus, as explained in Dr. Bauer's report, the department 

 has demonstrated the practicability of making magnetic measure- 

 ments on a moving ship, and the brig Galilee, chartered at San Fran- 

 cisco and refitted for this special purpose, is now engaged on such a 

 survey in the North Pacific Ocean. Considering that the oceanic 

 areas are in the aggregate about three times the aggregate of the 



