450 



SCIENCE. 



[N. S. Vol. VIII. No. 197. 



photometric measurements of variable stars, 

 and in the other general photometry system- 

 atically carried on by a number of obser- 

 vers. In the photographic enterprises there 

 was the charting of the stars of the entire 

 heavens once every year by means of the 

 eight-inch Bache and Draper photographic 

 doublets and smaller instruments, and the 

 photographic study of the Milky Way on 

 different scales by exposure of four or five 

 hours with the two and one-half inch, eight 

 inch and twenty- four inch Bruce telescopes. 



Photographic spectroscopy was repre- 

 sented by a general spectroscopic Durch- 

 musterung carried out by an eight- inch 

 telescope provided with an objective prism. 

 For details of the spectra of the brighter 

 stars there were present photographic 

 spectra given by the eleven-inch photo- 

 graphic telescope of the Harvard Observa- 

 tory and the thirteen-inch at Arequipa, 

 taken with from ' one to four objective 

 prisms. And for the spectra of very faint 

 objects the twenty-four-inch Bruce, armed 

 with its objective prisms, presented minute 

 details. Among the list of notable discov- 

 eries due to these organized methods of re- 

 search of Professor Pickering there were 

 shown the spectra of the invisible binaries, 

 the spectra of numerous bright line varia- 

 ble stars, the results of study on stars hav- 

 ing peculiar spectra, and in the wonderful 

 photographs of clusters, of definition proba- 

 bly surpassing any yet made, were disclosed 

 those hundreds of variable stars in which 

 Professors Pickering and Bailey have just 

 reason to express a proud delight. 



Whether the members of the Conference 

 were instructed in shrewd management of 

 stellar photography by Mr. King, or lis- 

 tened to the detailed explanation of the 

 methods of examining photographic spec- 

 tra by Mrs. Fleming or Miss Maury, with 

 the vast library of plates at their command, 

 or followed Professor Bailey in his most in- 

 teresting charting of the periods of hun- 



dreds of variables in the star clusters, or 

 discussed with Professor Searle the methods 

 by which he is bringing to completion the 

 Gesellschaft zone, or reviewed with Professor 

 W. H. Pickering problems in direct tele- 

 scopic observations, or with Mr. Wendell 

 they followed the highly accurate meas- 

 urements of stellar magnitude at the equa- 

 torial, or whether with any one of the other 

 observers they undertook to follow the 

 work, not omitting the special work with 

 the meridian photometer in which Professor 

 Pickering himself so actively participates, 

 one could not help feeling the presence of 

 a genius for organization and for the de- 

 terminate solution of vast scientific prob- 

 lems which alike instructed and inspired. 

 It would, therefore, be but just to record 

 the enthusiastic appreciation of the Confer- 

 ence for the contribution which the Direc- 

 tor of the Observatory of Harvard College 

 incidentally presented. 



Upon organization of the Conference Pro- 

 fessor Pickering briefly welcomed the Con- 

 ference to the hospitality and inspection of 

 the Observatory. The list of papers and 

 their discussion was then immediately 

 begun. 



The Conference was presided over alter- 

 nately by Professor J. R. Eastman, of the 

 United States Naval Observatory, and Pro- 

 fessor George E. Hale, Director of the 

 Yerkes Observatory, and the meetings were 

 not only held during the allotted time, 

 August 18th, 19th and 20th, but were car- 

 ried over to a series of adjourned meetings 

 held during the course of the subsequent 

 week. 



Professor Arthur Searle presented his ex- 

 perience on ' Personal Equation in Transit 

 Observations.' He showed that in two 

 observers' work there was a diiierence in 

 (1) the term A T + m, the ordinary per- 

 sonal equation; (2) the collimation micro- 

 metrically determined and computed from 

 transits ; (3) the apparent position of the 



