March 17, 1905.] 



SCIENCE. 



407 



W. S. Eichelberger and C. L. Doolittle 

 represented the society in the council of 

 the American Association for the Advance- 

 ment of Science. 



Hy request of a committee of the Na- 

 tional Academy of Sciences appointed to 

 secure international cooperation in solar re- 

 search, a committee from this society was 

 appointed by the president during the 

 preceding summer to cooperate with the 

 committee of the National Academy. The 

 council has made this a standing committee 

 of the society. 



PAPERS PRESENTED. 



C. L. Doolittle : 'The Constant of Aberration.' 

 John F. Haytord : ' A Test of . The Transit 



Micrometer.' 



Eric Doolittle : ' Remeasurement of the Hough 

 Double Stars.' 



D. P. Todd : ' Novel Design for Rotating Dome 

 Track.' 



Edward S. King : ' A Study of the Driving 

 Worms of Photographic Telescopes.' 



C. L. Doolittle: 'The Reflex Zenith Tube.' 



Annie J. Cannon : ' Variations of the Bright 

 Hydrogen Lines in Stellar Spectra.' 



Henrietta S. Leavitt : ' Variable Stars in 

 Large Nebulous Regions.' 



Percival Lowell : ' Planetary Spectrograms, 

 the Work of V. M. Slipher and C. 0. Lampland.' 



Percival Lowell: 'The Canals of Mars: An 

 Investigation of Their Objectivity.' 



Frank H. Bigelow : ' Note on Three Solar 

 Periods.' 



John A. Parkhurst: 'The Coordination of 

 Visual and Photographic Star Magnitudes.' 



Heber D. Curtis : ' The Quadruple System of 

 Alpha Geminorum.' 



Harold Jacoby : ' Use of the Method of Least 

 Squares to decide between Conflicting Hypothei^es.' 



Harold Jacoby : ' Tables for the Reduction of 

 Astronomical Photographs.' 



Edward C. Pickering : ' Recent Researches of 

 the Henry Draper Memorial.' 



Ormond Stone : ' Calibration of a Photographic 

 Photometer Wedge.' 



J. G. Hagen : ' Note on Two Variable Star Cata- 

 logues. 



' Useful Work for a Small Equatorial.' A 

 proposed discussion. To be opened by Edward C. 

 Pickering. 



ABSTRACTS OP PAPERS. 



The Constant of Aberration: C. L. Doo- 

 little. 



The systematic observation for variation 

 of latitude was begun by the author De- 

 cember 1, 1889. This work has been kept 

 up with some interruptions since that time. 

 In 1896 was begun at the Flower Observa- 

 tory a scries which it was proposed to con- 

 tinue on a uniform plan for a period of 

 seven years. This design was carried out 

 with but little departure from the original 

 program. Observation on this series was 

 terminated December, 1906. 



AVork is now in progress on a more com- 

 prehensive plan, two instruments being em- 

 ployed, viz., the 5|-inch zenith telescope 

 and the 8-inch "Wharton reflex zenith tube. 



The close of the former series seems to 

 mark the proper time for bringing together 

 the values of aberration constant which 

 have been obtained, and for combining 

 them to form a mean which may be con- 

 sidered final so far as may be shown by 

 these observations. 



The different values found are as fol- 

 lows : 



Sayee Observatory, South Bethlehem. 



Date. 



Aberration. 



No. Pairs. Wt. 



1889 Dec. 1—1890 Dec. l.S 

 1892 Oct. 10—1893 Dec. 27 

 18d4 Jan. 19—1895 May 16 



20".448 ±014 

 20 . 551±009 

 20 .537±014 



1479 i 

 2900 1 

 1989 ! 1 



Flower Observatory, Philadelphia. 



1896 Oct. 19—1898 Aug. 16 

 1898 Oct. 8-1899 Nov. 27 



1900 May 1901 Aug. 30 



1901 Oct. 3—1902 Dec. 1 

 1903 Jan. 22— 1903 Dec. 7 



20".580±008 

 20 .,540=i0]0 

 20 ..561*008 

 20 .513±009 

 20 .524 ±009 



2009 

 1303 

 1994 

 1935 

 1554 



1 

 2 

 2 

 2 

 2 



The reasons which have led to assigning 

 the wt. to the first determination will be 

 found fully set forth in connection with 

 the published results of this series.* For 

 various reasons which are fully explained 

 elsewhere the first series at the Flower Ob- 

 servatory is not thought to be as reliable 



* Transactions of the American Philosophical 

 Society, Vol. XX., p. 318. 



