April 5, 1918] 



SCIENCE 



337 



complete for the northern stars. Professor 

 Kapteyn has thus determined the magnitude 

 of about seventy thousand stars, which are 

 now in print in Harvard Annals, Vol. 85. 



Professor Pickering has also shown great 

 interest in developing useful work among 

 amateur astronomers. It is through him that 

 the chairman of the visiting committee has 

 been able to do some work on the asteroids. 

 Through lack of expert direction a large part 

 of the efforts of amateurs has proved of little 

 value. An exception to this rule has been the 

 Association of Variable Star Observers, which 

 was formed five years ago and has received 

 much encouragement and help from the di- 

 rector. 



During the last year this association of en- 

 thusiastic amateurs, consisting of thirty ob- 

 servers, has made eleven thousand two hundred 

 and fifty-two valuable observations of two 

 hundred and ninety variable stars of long 

 period. For this work the observatory has 

 furnished suitable charts and determined the 

 magnitudes of nearly five thousand stars 

 needed for reference, so that all are now meas- 

 ured on the same scale. At a meeting of the 

 Association of Variable Star Observers held 

 at the observatory in November, 1916, nine- 

 teen skilled observers made estimates of the 

 magnitude of the same object with the twelve- 

 inch telescope which showed an average differ- 

 ence of less than one-tenth of a magnitude — 

 an experiment altogether unprecedented. 



As these observers generally have access to 

 only small telescopes and are therefore imable 

 to measure variables when they are faint. Pro- 

 fessor "Wilson and Professor llitchel have 

 shown their spirit of cooperation by kindly 

 agreeing to continue the work with their six- 

 teen-inch and twenty-six-inch telescopes when 

 the stars are too faint to be measured by 

 smaller instruments. 



Also it should be mentioned that the ob- 

 servatory is cooperating with the other ob- 

 servatories of the world by furnishing magni- 

 tudes and classes of spectra in advance of 

 their regular publication in the Harvard An- 

 nals, which has been spoken of in previous 

 reports. 



These are some of the facts which show the 

 large way in which the observatory of Harvard 

 is interpreting its work, and give some idea 

 of how much Professor Pickering has done to 

 encourage friendly scientific cooperation both 

 here and abroad. 



The fruits of much of this work will mature 

 only in the future. 



Some of this cooperation the war has tem- 

 porarily broken but we look to the speedy re- 

 establishment of it when this world calamity 

 be overpast, and it will help to bind up the 

 wounds and soften the animosities which now 

 divide the nations. 



The publishing of astronomical discoveries 

 has not entirely ceased even now, and when 

 peace is at last declared the common interest 

 in the heavens will assert itself and bind to- 

 gether those whom the war has separated and 

 estranged. Thus the cooperative study of 

 astronomy will help to give us a new heaven 

 through the interpretation of a nobler science 

 and, through the good will which cooperation 

 aways brings, a new earth, in which dwelleth 

 righteousness. 



Joel H. Metcalf, Chairman, , 



George R. Agassiz, 



George I. Alden, 



Ingersoll Bowditch, 



Charles E. Cross, 



Samuel W. McCall, 



Herbert Parker, 



Frederick Slocum, 



Elihu Thomson 



SCIENTIFIC EVENTS 



THE MUSEUM OF THE UNIVERSITY OF 

 PENNSYLVANIA 



At THE close of its free public lecture sea- 

 son the officials of the University Museum call 

 attention to the recent progress of the insti- 

 tution and to some facts in connection with 

 its activities. 



Although only in its twenty-third year the 

 University Museum is already recognized 

 everywhere as one of the most important in- 

 stitutions of its kind in the world. Some of 

 its collections are the finest in existence, its 

 expeditions have gone to all parts of the globe, 



