OCTOBEK 7, 1998.] 



SCIENCE. 



457 



point out such streams of resistance. It is 

 possible that the tail of this comet swept 

 over a meteor stream or some other less 

 resisting medium in space on the 20th, 21st 

 and 22d of October, 1893. Portions of the 

 tail seemed to have been torn off and to be 

 drifting away from the comet as independ- 

 ent masses, and, if our ideas of comets are 

 correct, these might themselves become 

 swarms of meteors. 



The series of photographs shown indi- 

 cated the valuable results attained and the 

 wide field of study opened by this method 

 of research. 



Mr. A. Lawrence Eotch gave ' A Brief 

 Account of the Work of the Blue Hill 

 Meteorological Observatory,' in which he 

 described the peculiar instruments used, and 

 adverted to the scientific character of the 

 work carried on. His account was accom- 

 panied by photographs of the instruments, 

 and on closing the description he invited 

 the Conference to an inspection of the Ob- 

 servatory, which was cordially accepted 

 and participated in by many of the mem- 

 bers. Those who visited the Blue Hill Ob- 

 servatory were greatly impressed with the 

 methods and appliances used in the difficult 

 problems of meteorological research there 

 attempted. 



Miss A. C. Maury read a paper on ' The 

 K Lines of /J Aurigse.' She said /3 AurigEe 

 is a double star whose components revolve 

 in a period of 3'' 23" 37°" approximately, and 

 with a velocity in the line of sight of 150 

 miles a second. As the distance between 

 their centers, supposing the plane of the 

 orbit to pass through the sun, is only 

 about eight million miles, the stars are, 

 of course, inseparable by the telescope, 

 but their spectra become separated when, 

 in the course of revolution, one star is ap- 

 proaching the earth and the other receding 

 from it. By the Doppler principle, all the 

 lines of the combined spectrum then appear 

 double, those of the star approaching being 



shifted toward the violet, those of the star 

 receding, toward the red. 



Photographs of the double spectrum, two 

 hundred in number, obtained at the Harvard 

 Observatory during the past nine years, show 

 that the K line (of calcium) varies period- 

 ically in intensity. It is stronger in one 

 star in the photographs of one year and in 

 the other star in those of the year following, 

 the relative intensity thus alternating for 

 nine years. This variation, though less 

 perceptible, may extend to other lines of 

 the spectrum. It seems probable that the 

 revolving stars, which are nearly or quite 

 alike in mass and constitution, induce in 

 one another reciprocal variability. 



A similar variation has been suspected 

 by Professor S. I. Bailey in the components 

 of the Spectroscopic binary //' Scorpii, as 

 shown in the Photographs obtained in Peru. 



Professor Winslow Upton presented the 

 methods of determining ' The Position oi 

 the Arequipa Station of the Harvard Col- 

 lege Observatory.' The latitude of the 

 Arequipa station was obtained by observa- 

 tions in the prime vertical made with a 

 special instrument designed by the late 

 Professor William A. Rogers. The obser- 

 vations were made by two Besselian meth. 

 ods, the extreme range for individual ob- 

 servations being 7". The final value for 

 the latitude is —16° 22' 2S".0±0".19. The 

 longitude was obtained by telegraphic ex- 

 change of time signals between Arequipa 

 and Arica, Chile, the longitude of the latter 

 station having been determined in 1883 by 

 officers in the United States l^avy by means 

 of the coast cables. The difficulties ox 

 making the exchange directly made it 

 necessary to repeat the signals in passing 

 from the land telegraph line to the cable. 

 The difference of longitude was determined 

 with a probable error of ±0'.032, and the 

 resulting longitude is 4''4:6"'11'.71 west of 

 Greenwich. 



Mr. Henry M. Parkhurst, in a paper on 



