404 SCIENTIFIC RECORD FOR 1885. 



revolution, and hence upon the lengths of the day and year. Professor 

 Oppolzer (Astr on., Nachr., 2573) has discussed the amouutof these actions, 

 and has computed the density which the meteoruid matter must have in 

 order to produce the observed and unexplained acceleration of the moon's 

 mean motion. But a- body that passes near to tbe earth has also an 

 action of like character due to the attraction of gravitation alone, and 

 Professor Newton proceeds to calculate its amount. The conclusion at 

 which he arrives is that the effect upon the earth's motion of the meteors 

 that come into the earth's atmosphere exceeds at least one hundred fold 

 that of the meteors that pass by without impact. (Observatoty.) 



Determination of longitudes in South America. — According to Science 

 (vol. V, p. lol), Commander Davis has just completed his important 

 telegraphic determinations of longitude on the western coast of South 

 America. The great chain connecting Washington with different points 

 in South America, and then extending through Saint Vincent, Madeira, 

 Lisbon and Greenwich, is now closed with but an insignificant discrep- 

 ancy. 



The proposed ehange in the beginning of the astronomical day. — No gen- 

 eral agreement has been reached by astronomers upon the sixth resolu- 

 tion of the Washington Meridian Conference, which recommends that 

 the astronomical and nautical days be arranged everywhere to begin at 

 mean midnight. The matter was brought up at the Geneva meeting of 

 the Astronomische Gesellschaft in 1885. (See Vrtljhrschr., 20, p. 227- 

 31.) Struve, Folic, and Pechiile seemed to be the only members present 

 in favor of the change, while Newcomb, Weiss, Krueger, Duner, Auwers, 

 Tietjen, and Safarik spoke in opposition to it. Mr. Downing, of the 

 GreenwichObservatory, says (iV<if?tre, 32:353), " - - - and judging 

 from the individual expressions of opinion that have been published, 

 I should imagine that here, as at Geneva, the majority of real workers 

 in our science (with the probable exception of those engaged in solar 

 work) would be opposed to the proposed change." 



In the United States, official action has been taken by the Secretary of 

 the Navy, referring the question to the National Academy. The report 

 (Senate Ex. Doc. No. 67, Forty-ninth Congress, first session) of a com- 

 mittee of that body consisting of Pres. F. A. P. Barnard, Profs. A. Gra- 

 ham Bell, J. D. Dana, S. P. Langley, Col. Theodore Lyman, Profs. E. C. 

 Pickering, and C. A, Young says : " The committee regard favorably the 

 proposition of the meridian conference on this subject, and recommend 

 that the change should be made as soon as sufficient concert of action 

 can be secured among the leading astronomers and astronomical estab- 

 lishments of the civilized world — in 1890, if practicable ; if not, in 1900." 



It would seem to be incumbent on those astronomers who have ex- 

 pressed themselves in favor of the proposed change, and of the conse- 

 quent interruption of astronomical chronology, to justify strongly their 

 position. It is not quite clear that this has been done, for while many 

 reasons are given against the change, almost the only argument in its 



