Decembee 6, 1901.] 



SCIENCE. 



881 



asteroids and variables should similarly be 

 followed ; the observations of the satellites 

 should be continued with this instrument, 

 especially those of Saturn and Uranus, 

 which are likely to be neglected at Euro- 

 pean observatories for the next few years 

 owing to their southern declinations. 



Lost asteroids, and perhaps others, can 

 best be found and followed by photography. 

 The spectroscopic approach and recession 

 of the stars is at the present time under 

 investigation with so many very large tele- 

 scopes that this work may be left to them. 

 The number of known spectroscopic bi- 

 naries, however, is so great that it may be 

 necessary hereafter to follow them carefully 

 to determine the laws governing their mo- 

 tions. The work of the 12- inch equatorial 

 should supplement that of the 26-inch. 



In general the plan of work should be 

 altered but rarely, and then only when 

 changes seem imperative. Special atten- 

 tion should be given to work neglected 

 elsewhere, and every efifort made to render 

 our knowledge of astronomy as complete 

 as possible. 



AMERICAN EPHEMERIS AND NAUTICAL 



ALMANAC. 



Among the most important scientific 

 publications of the Government of the 

 United States are those issued by the Office 

 of the American Ephemeris and Nautical 

 Almanac. The first and best known is the 

 Almanac issued every year, which gives 

 name to the office. Four European coun- 

 tries — Great Britain, Germany, France 

 and Spain — make similar publications, and 

 a great saving might be efi'ected by carry- 

 ing still further the plan of cooperation 

 already in part adopted. To avoid errors 

 certain elements are computed independ- 

 ently three times, but if this is done for all 

 five of the almanacs evidently much work 

 is wasted. So far as possible the same 

 quantities should be published in all of the 



almanacs, and computed independently as 

 many times as may be deemed necessary. 

 Ninety-six pages are devoted to that im- 

 portant and laborious problem, the exact 

 path of the moon. Here an independent 

 computation seems needless when we con- 

 sider that the only American observatory 

 at which the position is regularly deter- 

 mined is at Washington. The occasional 

 observations made at other places have, in 

 general, but little permanent value, and 

 for observations of the moon at sea far less 

 accurate positions are needed. In fact, 72 

 additional pages are devoted to lunar dis- 

 tances. In order that the saving suggested 

 may be accomplished without delaying the 

 publication of the Almanac, arrangements 

 should be made with the foreign almanac 

 offices to complete their computations at 

 least a year longer in advance than is done 

 at present. 



A second most important consideration 

 is that changes should be made only after 

 a most careful examination and consulta- 

 tion with astronomers for whose benefit 

 the Almanac is printed, and with the ap- 

 proval of the Board of Visitors. Changes 

 not only cause great inconvenience, but 

 often render it necessary to employ some 

 other almanac when reducing the observa- 

 tions extending over a long period of years. 

 The changes suggested below are so ex- 

 tensive that they should be made only if 

 approved by American astronomers in gen- 

 eral. 



Washington mean time is not used even 

 at Washington, and its use in the Almanac 

 seems superfluous. Greenwich mean time, 

 as modified in standard time, is in univer- 

 sal use in the United States, and is already 

 used in a large part of the Almanac. Cen- 

 tral time, which difi'ers from Greenwich 

 time by exactly six hours, might be con- 

 veniently used to simplify the interpolation 

 for the transits of the moon and planets. 



The phase angle, i, should be given for 



