October 31, 1902.] 



SCIENCE. 



689 



without thanking you one and all for your 

 presence here. I am well aware that it is 

 no personal testimonial to me. Many of 

 you I have met to-day for the first time 

 and although I shall hope to liave many 

 opportunities of cultivating an acquaint- 

 ance so pleasantly begun yet it is possible 

 that many of us may never, meet again. 



Your presence here, however, is a testi- 

 mony to the essential oneness in aim and 

 in spirit of our American institutions of 

 higher learning; it is an evidence of sym- 

 pathy and good fellowship ; it is earnest of 

 cooperation and emulation for all good 

 things. 



We who are gathered together here as 

 students, professors, trustees, benefactors, 

 friends, of American colleges and universi- 

 ties may congratulate ourselves. We have 

 surely followed Emerson's injunction and 

 hitched our wagons to the stars. Every 

 one of us may be glad that it has been per- 

 mitted to him to take a part, however hum- 

 ble, in the great work of laying the founda- 

 tion and erecting the superstructure for a 

 series of institutions from the Atlantic to 

 the Pacific, from the Great Lakes to the 

 Gulf, which shall do for us and our civili- 

 zation what the universities of the Old 

 World have done for Europe. 



Surely we may rejoice if we can help to 

 win for our country the same proud posi- 

 tion in education and science which our 

 fathers and brothers have won for it in 

 industry and commerce. 



ON THE POSITIONS OF THE NORTHERN 

 CIRC'UMPOLAR STARS.* 



The importance of knowing the positions 

 of the fixed stars has been recognized from 

 the time of tJie early Greek astronomers, and 

 the accuracy demanded has increased with 

 the progress of the science. During the 



* Paper read before Section A, American Asso- 

 ciation for the Advancement of Science, Pitts- 

 burgh meeting, 1902. 



past two hundred years an enormous 

 amount of labor has been expended in 

 forming catalogues of the stars, and fur- 

 ther progress in this direction is recognized 

 to-day as one of the principal needs of as- 

 tronomy. Not only ought a larger number 

 of stars to have their places accurately 

 measured, but the positions of many of the 

 so-called fundamental stars should be more 

 precisely determined. 



Since the motions of the Sun, Moon and 

 larger planets are confined to the region of 

 the sky known as the Zodiac, the equatorial 

 and zodiacal stars have been more frequent- 

 ly observed and their positions more accu- 

 rately determined than is the case in gen- 

 eral with the cireumpolar stars. Compari- 

 son stars are needed near the pole only on 

 those rare occasions when a comet crosses 

 that region of the sky. 



Beginning with the epoch-making obser- 

 vations of Bradley about one hundred and 

 fifty years ago, the work of determining 

 fundamentally, that is with reference to the 

 equator and equinox, the places of a limited 

 number of equatorial and cireumpolar stars 

 has been carried on continuously at Green- 

 wich. Since its foundation about 1840, 

 work of the highest value has been done by 

 the National Observatory of Russia at Pul- 

 kowa, near St. Petersburg. Fundamental 

 work of this kind has also been done at 

 various other observatories, mostly Euro- 

 pean, and by professional astronomers, no- 

 tably by Bessel and Struve. 



Valuable differential work on the cireum- 

 polar stars has been done by amateur as- 

 tronomers, whose work has been based on 

 the positions of fundamental stars previous- 

 ly determined. Some of the noblest ex- 

 amples of devotion to science are found in 

 the history of this subject. 



Perhaps the most remarkable case is that 

 of Stephen Groombridge. a linen draper of 

 London, who about 1802 set up a transit 

 circle by Troughton of three and one half 



