882 



SCIENCE. 



[N. S. Vol. XIV. No. 362. 



the outer planets as well as for Mercury 

 and Venus. 



The ephemerides of the satellites are 

 often insufficient for even the identification 

 of these bodies. This is particularly the 

 case with Hyperion and lapetus. For the 

 latter even the apparent ellipse is not 

 given. It will probably not be necessary 

 to return to the bulky tables of the satellites 

 of Jupiter, published yearly in the Almanac 

 before 1882. It would be convenient to 

 have the correction to the ephemeris given 

 when it is known — for instance, the ephem- 

 eris of Mimas for this year (1901) is in 

 error by about four hours. Accordingly it 

 is invisible on account of the ring at the 

 predicted times of elongation. 



The published positions of observatories 

 should be changed only after careful con- 

 sultation with the directors. If a system 

 of longitude like that of the Coast Survey 

 is adopted, it should be so stated in the de- 

 scription. The statement that ' the latest 

 available data have been used ' is too in- 

 definite. 



A great saving in expense might be ef- 

 fected by the adoption of some of the 

 changes mentioned above. This would 

 permit the insertion of valuable data now 

 omitted. For instance, the list of star 

 places might be greatly extended, epheme- 

 rides for physical observations of the moon 

 and planets might be inserted, and approxi- 

 mate ephemerides of Eros and of some of 

 the more interesting asteroids, such as 

 Hungaria, Tercidina, Sirona and Poly- 

 hymnia. 



It is recommended that these and simi- 

 lar changes be proposed to astronomers, 

 and that they be invited to suggest others, 

 as was done by Professor Newcomb when 

 taking charge of the office. 



A series of papers of very great scientific 

 value, entitled • Astronomical Papers pre- 

 pared for the use of the American Ephem- 

 eris and Nautical Almanac,' has been 



issued by this office during the last twenty 

 years. The ' Contribution to Celestial 

 Mechanics,' made while the office was un- 

 der the direction of Professor Newcomb, 

 was a notable one, and a continuation of 

 the papers mentioned is greatly to be de- 

 sired. A continued investigation of the 

 motion of the moon is especially recom- 

 mended. 



INSTRUMENTS. 



The Board at its meeting in April ap- 

 pointed a committee which made as care- 

 ful an inspection of the instruments of the 

 Observatory as was possible during the 

 time at its disposal. On the whole, the 

 26-inch equatorial is in good condition. It 

 is recommended that this instrument be 

 supplied with a micrometer at least equal 

 in quality to that constructed for the large 

 equatorial of the Pulkowa Observatory. 

 Also a good field illumination should be 

 provided, as well as a symmetrical illumi- 

 nation for the wires. 



Since the visit of the committee in April 

 a number of improvements have been made 

 on the 12-inch equatorial ; a bright field 

 illumination is still needed. An investiga- 

 tion of the object glass, which gives poor 

 stellar images, is now in progress by Mr. 

 King, the officer in charge. This examina- 

 tion will show whether the glass is merely 

 out of adjustment or should be refigured. 



Extensive repairs are needed for the 

 9-inch transit circle, and especial attention 

 is invited to Exhibit B, which gives a list 

 of the most important improvements re- 

 ferred to. 



A number of changes have been made in 

 the 6-inch transit circle ; these and others 

 still needed are referred to in Exhibit C. 

 For both transit circles collimators should 

 be provided having object glasses of larger 

 apertures, and also better means should be 

 provided for obtaining the necessary me- 

 teorological data. 



The prime vertical transit should be pro- 



