INTERNATIONAL UNION FOR COOPERATION IN 



SOLAR RESEARCH. 



Hv w. shackli:to.\. f.k.a.s.. a.k.c.s. 



Thk fourth Conference of the International Union 

 for Cooperation in Solar Research was held at the 

 Solar Observator}- of the Carnegie Institution, Mount 

 Wilson, California, from Aug. 30th to Sept. 3rd, 

 and several representa- 

 tives from this countr\- 

 were present. Previous 

 conferences have been 

 held at St. Louis, Oxford 

 and Paris. The meetings 

 are now triennial, and the 

 next is arranged to take 

 place in Germany. 



Great Britain was 

 represented bv Rev. A. L. 

 Cortie, S.J., Professor F. 

 W. Dyson, Professor A. 

 Fowler, Major E. H. 

 Hills, Sir Joseph Larmor. 

 Professor H. F. Newall. 

 Professor A. Schuster and 

 Professor H. H. Turner. 

 Other distinguished as- 

 tronomers and ph\'sicists 

 from Germany, Russia, 

 France, Austria, Holland, 

 Italy, Switzerland and 

 Sweden were also present, 

 together with a large 

 gathering of the American 

 astronomers. 



The proceedings of the 

 conference consisted of 

 the discussion of the re- 

 l)orts of the various com- 

 mittees appointed at the previous conference, at 

 Meudon, in 1907, to investigate solar radiation, sun 

 spots, solar rotation and standards of wave-length. 

 The International Eclipse Committee also met. and a 

 new committee was appointed to consider the 

 important subject of the classification of stellar 

 spectra, as, obviously, solar research can be materially 

 assisted by a study of the manv stars with svhich it 

 is so intimately related spectroscopicalh-. 



These proceedings, when published, will form the 

 third volume of the "Transactions of the Inter- 

 national Union for Cooperation in Solar Research."" 



Hn route to Mount \\'ilson Solar Observatorv manv 

 of the astronomers took part in the meeting of the 

 .\stronomical and Astrophysical Society of America. 

 This Societ\' meets once a vear, as American astron- 

 omers are scattered over the whole of the continent, 

 and cannot readih' meet at shorter intervals, the 



Tower Telescope, Solar Observatory, 

 California, 



selected place of meeting of the Society this year 

 being Harvard College. Here several papers on 

 Hallev"s comet were read by Professor Barnard and 

 others, together with a [laper on the results of the 



Societv"s expedition to 

 "^ Hawaii to observe the 

 comet. These were 

 supplemented by a paper 

 from Professor Fowler, 

 on the "Spectroscopic 

 Features of the Head 

 and Tail of Comets."" 

 This paper elicited some 

 discussion and received 

 warm approbation. 



Another interesting 

 paj)er was read by Mr. 

 Joel Stebbins on "The 

 Measurement of the light 

 of Stars with a Selenium 

 Photometer, and its 

 application to the varia- 

 tions of Algol."" He 

 showed that Algol has a 

 second minimum, and 

 that the light curve 

 between the two minima 

 is not flat. The results 

 derived from this research 

 indicate that the dark 

 companion to Algol is not 

 black 

 light than the Sun 



The obsers'atories at 

 Harvard College, under 



but gives off more 



Mount Wilson, 



the Directorate of Professor Pickering were thrown 

 open to inspection : it may be mentioned that the 

 5 -foot reflector formerl\- belonging to the late Dr. 

 Common forms a part of the equipment of this 

 observator)-. 



During the week preceding tlie Conference many 

 of the part}- crossing from East to West visited the 

 Flagstaff Observatory, Arizona, where Professor 

 Lowell personally welcomed the astronomers, and 

 showed man\- of his photographs and drawings of 

 Mars, 



On arrival at Pasadena the physical laboratory, 

 workshops and computing establishment were 

 inspected, the astronomers then gradually made 

 their wa\- up tlie mountain trail to the summit of 

 Mount Wilson (altitude 5,886 feet), where the 

 observing portion of the observatory is situated. 



Bevond extending a heartv welcome to the 



465 



