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SCIENCE 



[N. S. Vol. XXXVI. No. 927 



stars measured in this way indicated a 

 probable error of only a hundredth of a 

 second of arc. 



The criticism that, in America, we were 

 not doing our share of the study of the 

 position of the stars, seemed to be a just 

 one. Accordingly, as president of the As- 

 tronomical and Astrophysical Society of 

 America, I appointed a committee to rem- 

 edy this defect as far as possible, and 

 selected Professor Schlesinger as its chair- 

 man. Some of the results so far obtained 

 will be announced at the present meeting 

 of the society. Besides the work already 

 described, admirable results in astrophys- 

 ics have recently been obtained at the 

 Allegheny Observatory by the director, in 

 measuring the motion of the stars in the 

 line of sight, a problem now receiving more 

 attention than any other in many of the 

 principal observatories of the world. Of 

 this problem, it is sufficient to say that to 

 obtain results of the accuracy attained else- 

 where, it is necessary to have a telescope 

 of the largest size, a spectroscope of the 

 most approved form, and measures and 

 reductions of the photographs of the great- 

 est possible accuracy. 



You will thus see that, as already stated, 

 you have secured an astronomer and placed 

 him in charge of your observatory, who 

 has shown great skill and efficiency in both 

 the old and the new departments of astro- 

 nomical research. You have before you a 

 beautiful and suitable building and an 

 equipment of instruments of the highest 

 grade. All of those conditions are most 

 favorable, but the future success will now 

 depend largely on you. Allegheny is 

 doubtless a very different place intellectu- 

 ally from what it was when Langley was 

 here, but one of his principal sources of 

 discouragement was the lack of interest in 

 his work, and a failure to appreciate his 

 success by his friends, with a few notable 



exceptions. I hope that you will follow 

 the work of the Allegheny Observatory 

 closely, and I am sure that you will find 

 the results of interest and value. A large 

 force of observers and computers is needed 

 to derive the best results from an equip- 

 ment such as is collected here. The num- 

 ber of officers at several of the largest 

 observatories is thirty or forty, and such a 

 force is required to complete in a reason- 

 able time some of the great problems which 

 now form the most important contribution 

 which can be made to astronomy. For 

 example, suppose that an astronomer has 

 developed by long and careful study the 

 best method of attaining a certain result 

 with an instrument costing many thou- 

 sands of dollars. He can almost always 

 instruct a younger and less able man than 

 himself to repeat his work on other stars. 

 A research can thus be extended, at small 

 additional expense, to hundreds or perhaps 

 thousands of stars, until the entire avail- 

 able time of the instrument is occupied. 

 In visual observations of the stars, this 

 time is greatly restricted by clouds, twi- 

 light, moonlight and other causes, while a 

 photograph exposed for a few minutes may 

 furnish material for weeks of study. After 

 a photograph is measured, there is often a 

 long and laborious computation to be un- 

 dertaken, which can be carried on by un- 

 skilled computers after they have been 

 taught the exact method. The results are 

 of no value unless they are made known to 

 the world by publication. This involves 

 laborious copying, arranging material in 

 suitable form, reading of proof and other 

 work involved in publication, in addition 

 to the actual cost of printing. It is evi- 

 dently very poor economy to establish an 

 extensive plant, and then fail to work it to 

 its full capacity. A steamer which should 

 be idle for ten or eleven months every year 

 would prove a very poor investment. In 



