INTERNATIONAL ORGANIZATION 413 



astronomical telegrams ; dynamical astronomy and astro- 

 nomical tables ; meridian circle observations, including the 

 study of atmospheric refraction ; optical investigations, both 

 theoretical and applied, relating to astronomical problems and 

 the physical study of instruments ; solar radiation ; registration 

 of the velocities of solar vapors; the solar atmosphere; ex- 

 peditions for the observation of eclipses and other astro- 

 nomical phenomena ; standards of wave-length and solar 

 spectrum tables ; solar rotation ; physical observations of 

 planets ; nomenclature of lunar phenomena ; determination of 

 longitudes by wireless telegraphy ; variation of latitude ; minor 

 planets ; comets ; meteors ; the International Chart of the 

 Heavens ; stellar parallaxes ; stellar photometry ; double stars ; 

 variable stars ; nebulae ; classification of stellar spectra ; stellar 

 radial velocities ; time standards and determinations ; and the 

 reform of the calendar. This bare enumeration can give lit- 

 tle conception of the importance of the work of the Astro- 

 nomical Union, but if it were feasible in the available space 

 to outline the work of some of these committees, and to indi- 

 cate the advantages that must result from a combined attack 

 on astronomical problems, in which the ablest investigators 

 will utilize the instrumental resources of scores of great ob- 

 servatories in accordance with a general plan of operations, 

 the true possibilities of such united effort would become ob- 

 vious. 



The scope of the International Union of Geodesy and 

 Geophysics is no less comprehensive. Its objects are to en- 

 courage the study of problems relating to the figure and physics 

 of the earth, to initiate and coordinate investigations requiring 

 the cooperation of several countries, and to facilitate special 

 investigations, such as the inter-comparison of instruments. 

 The Union is constituted of six Sections, dealing with (i) 

 Geodesy, (2) Seismology, (3) Meteorology, (4) Terrestrial 

 Magnetism and Electricity, (5) Physical Oceanography, (6) 

 Volcanology. Each of these Sections appoints special inter- 

 national committees, similar to those of the Astronomical Union, 



