452 



SCIENCE. 



[N. S. Vol. XXIII. No. 586. 



positions of polar stars to apparent place 

 is so great as to preclude the method be- 

 coming of much practical value. 



The Hough BouUe Stars: Eric Doo- 



LITTLE. 



Work on the 622 double stars discovered 

 by Hough has been carried on, only about 

 50 of them now remaining unmeasured. 

 It is hoped that these may be finished dur- 

 ing the present year. 



The Observations of Sun-spots by the Late 



C. E. P. Peters: Edwin B. Frost. 



It has been for many years a matter of 

 regret to students of the sun that the solar 

 observations by this careful observer have 

 remained inaccessible. In 1904 the Car- 

 negie Institution decided ta publish them, 

 and the writer was requested to edit them. 



The observations cover the decade from 

 May, 1860, to May, 1870, with some inter- 

 ruptions, and more than 13,000 heliographic 

 positions of spots were accurately deter- 

 mined on over 1,100 days. The first year's 

 observations overlap the last year of Car- 

 rington's series, and Spoerer's observations 

 at Anclam extend from 1861 to 1871. 

 While it is thus decidedly ' unfortunate 

 that Peters 's results could not have been 

 published thirty-five years ago, their value 

 for comparative purposes is still great, and 

 they were obtained with better instru- 

 mental equipment than the other two con- 

 temporary series. 



The manuscript was supposed to have 

 been left by Dr. Peters in a condition for 

 printing, but some abridgment of the tab- 

 ular data has now seemed desirable. No 

 manuscript has been found describing the 

 method of observation or procedure used 

 in obtaining the constants of reduction, 

 which constants in fact have to be inferred. 

 The galley proofs of the tabular part have 

 now been read, and it is hoped that the 

 volume can be issued during 1906.yfe 



Computed Tracks and Totality-durations of 

 Total Solar Eclipses in the Twentieth 

 Century: David Todd and Robert H. 

 Baker. 



Their tracks of visibility have been calcu- 

 lated and charted as accurately as possible. 

 This has been done from Oppolzer's tables 

 (Canon der Finsternisse) , the most reliable 

 at present in existence, and Oppolzer's own 

 charts corrected. The longest eclipses of 

 the next half-century are : 



1911, April 28, 

 1919, May 29, 



1922, September 21, 



1923, September 10, 

 1926, January 14, 

 1929, May 9, 

 1937, June 8, 

 1940, October 1, 

 1944, January 25, 

 1947, May 20, 

 1955, June 20, 



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 minutes. 



An Analytical Method of Determining 

 Orbits of New Satellites: A. 0. Leusch- 



NER. 



This paper contains formulfe for the com- 

 putation of osculating elements of a ma- 

 terial point moving under the attraction 

 of more than one mass, from three or more 

 geocentric observations. It is applicable 

 to satellites, comets or asteroids which are 

 greatly disturbed during the time over 

 which the observations available for the 

 computation of an orbit extend. The re- 

 sulting osculating elements are the elements 

 that would result from a solution irrespec- 

 tive of the perturbations if the observed 

 right ascensions and declinations of the 

 material point could be corrected in ad- 

 vance for the perturbations, starting with 

 an arbitrary epoch of osculation within the 

 range of the observations. As in the short 

 method proposed by the writer for deriving 

 orbits of comets and asteroids, the right 

 ascension (a) and declination (8), their 

 velocities (a', 8'), and accelerations (a", 8"), 



