54 



ASTRONOMICAL PHENOMENA AND PROGRESS. 



the direction in which the motion of Sirius for 

 a hundred years past had shown that some re- 

 volving satellite must be found. It was there- 

 fore a case in which the direction of the body 

 had been indicated by its attraction upon an- 

 other body, before its existence had become 

 known. For a few years observations showed 

 that the motion of the satellite around its pri- 

 mary was more rapid than that which had been 

 indicated by theory, the difference in two direc- 

 tions amounting to nearly 10. But the obser- 

 vations made by Prof. Hall and other observers 

 in 1884 showed that the satellite is now rapid- 

 ly approaching the planet, and that its position 

 is coming more and more into agreement with 

 the old calculations. In a very few years it 

 will be so close to Sirius that it is questionable 

 whether even the most powerful telescope will 

 be able to distinguish it. According to Dr. 

 Auwers, the nearest approach will take place 

 in the year 1891. 



The International Meridian Conference. Among 

 the many events of the year pertaining to as- 

 tronomy we must include the work of the In- 

 ternational Conference that met in Washington 

 during the month of October, 1884, for the 

 purpose of deciding upon a common prime 

 meridian and a common system of time to be 

 used by all nations. The bill authorizing the 

 President to invite the Conference became a 

 law in the year 1882. Before issuing a formal 

 invitation, it was judged best to inquire in 

 advance whether foreign nations were ready 

 to enter upon the discussion of the question. 

 These preliminary inquiries showed that some 

 governments were ready to receive proposals 

 favorably, while others delayed an answer, 

 waiting a preliminary discussion of the subject 

 by the International Geodetic Association of 

 Europe. This body met at Rome in October, 

 1883. Besides the regular members of the 

 association, the Astronomer Royal of England 

 and a delegate from the Coast Survey of the 

 United States were present. The association, 

 after considerable discussion, adopted the fol- 

 lowing conclusions bearing upon the subject, 

 the preliminary remarks being omitted : 



II. That the Conference propose to the Government 

 to choose for the initial meridian that of Greenwich, 

 in:ismuch as that meridian fulfills, as a point of de- 

 parture of longitudes, all the conditions required by- 

 science ; and that, being already actually the most ex- 

 tensively used of all, it presents'the greater probability 

 of being generally accepted. 



III. That the longitudes should be reckoned from 

 the meridian of Greenwich in the sole direction from 

 east to west, and from zero to 360, or from zero to 

 twenty-four hours ; the meridians on the charts and 

 the longitudes in the registers should be indicated 

 everywhere in hours and minutes of time, with liberty 

 of adding the indication of the corresponding degrees. 



IV. That the Conference recognizes for certain 

 scientific needs, and for the service of the great ad- 

 ministrations of the means of communication, such as 

 railways, steamship lines, telegraphs, and posts, the 

 utility or adopting a universal hour,_ side by side with 

 the local or national hours, which will necessarily con- 

 tinue to be employed in civil life. 



V. That the Conference recommends, as the point 

 of departure of the universal hour and of cosmopolitan 



dates, the mean noon of Greenwich, which coincides 

 with the instant of midnight or with the beginning of 

 the civil day, situated at the twelfth hour, or at 180 

 Greenwich. It follows that the universal time will 

 correspond everywhere with the mean local time, 

 reckoned from midnight, less twelve hours and the 

 longitude of the place, and that the dates change at 

 the antipodes of Greenwich. 



VI. That it is desirable that those states which, in 

 order to adhere to the unification of longitudes and of 

 hours, will have to change their meridians, should 

 adopt the new system of longitudes as quickly as possi- 

 ble an their observatories and official almanacs, in their 

 geodetical, topographical, and hydrographical works, 

 and in their new charts. As a means of transition it 

 would be well that in new editions of old charts, on 

 which it would be difficult to change the squares, the 

 indications according to the new system should at 

 least be inscribed alongside the enumeration of the 

 old meridians. 



VII. That these resolutions should be laid "before 

 the governments and recommended to their friendly 

 consideration with the expression of a hope that an 

 International Convention, confirming the unification of 

 longitudes and of hours, may be concluded as quickly 

 as possible by a special conterence. 



These conclusions of the Roman Conference 

 indicated that an agreement upon the subject 

 was possible. The formal invitation from our 

 Government was therefore sent in the month 

 of December, 1883, to all nations with which 

 it was in diplomatic communication. The 

 date fixed for the Conference was October 1, 

 1884. Each nation was requested to send not 

 more than three conferees, but this number was 

 afterward increased to five. For the most part 

 the foreign nations were represented by their 

 diplomatic envoys resident in Washington, but 

 England, France, and Russia, as well as Brazil, 

 and a few other states, sent one or more special 

 conferees. The Conference met at the ap- 

 pointed time, in the Department of State at 

 Washington, and Rear-Admiral C. R. P. Rod- 

 gers, the senior member of the American dele- 

 gation, was chosen president. The point which 

 was most warmly discussed was whether the 

 universal prime meridian to be adopted should 

 be that of Greenwich. The most vigorous op- 

 position came from the French representatives, 

 whose spokesman was M. Janssen, the emi- 

 nent astronomer of the Institute of France. 

 This gentleman took the ground that, to be 

 entirely acceptable to all, the prime meridian 

 should not be fixed with reference to the capi- 

 tal of any one nation, but should be entirely 

 " a neutral meridian," chosen solely with refer- 

 ence to geographical considerations. He main- 

 tained that a meridian passing through Behring 

 Strait would fulfill the requirements better than 

 any other. When, after a prolonged discus- 

 sion, extending through several sessions, the 

 question was finally put to vote, the meridian 

 of Greenwich was adopted, with the single dis- 

 senting vote of San Domingo, the representa- 

 tives of France and Brazil refraining from 

 voting. 



The next important subject considered by 

 the Conference was that of a system of uni- 

 versal time to be used for all purposes where 

 it should be found convenient. This also led to 



