172 Notices respecting New Books, 



three times daily), and the principal railways in the Southern States. 

 The transit-instrument and mural circle were under the charge of 

 Professor Yarnall ; and Professor Eastman had charge of the Me- 

 teorological Observations. 



The attention of Professor Newcomb has been given chiefly to the 

 theory of the moon, for the purpose of revising both the theory and 

 the tables, in the course of which a new and more exact method of 

 computing the effect of the attraction of the planets has been 

 worked out. The results of the Professor's work indicate that the 

 positions of the moon at the total eclipse of 1715 and at the epochs 

 of two occupations of Aldebaran observed at Greenwich and London 

 in 1680, are better represented by the old tables of Burckhardt than 

 by those of Hansen. 



The introductory part of the volume contains very full descrip- 

 tions of each instrument, its various adjustments, method of ob- 

 serving adopted, determination of corrections, &c. These notices 

 embody various important practical details which it is next to im- 

 possible to find in any popular treatise, but which are essential for 

 the training of an efficient amateur astronomer. We need not en- 

 large on the high value of the observations recorded. 



The volume contains four appendices. Appendix I. embodies 

 the operations for determining the difference of longitude between 

 Washington and St. Louis. The work was effected by the aid of 

 the Western Union Telegraph Company in exchanging signals— 

 the observations and reductions at St. Louis being made by the 

 officers of the United-States Coast Survey, and those at Washing- 

 ton by the officers of the Observatory. 



Appendix II., "Eeports on Observations of Encke's Comet during 

 its return in 1871," has already been noticed in our pages. 



Appendix III., " On the Eight Ascensions of the Equatoreal 

 Fundamental Stars," by Professor Newcomb, contains much valuable 

 information. The object the Professor had in view was to reduce 

 the right ascensions of different catalogues to a mean homogeneous 

 system. We may possibly return to this Appendix on some future 

 occasion. 



Appendix IV. contains the zones of stars observed at the Naval 

 Observatory with the meridian transit-instrument hi the years 

 1846 to 1849— a portion of the great work originally contemplated, 

 but discontinued on account of the difficulty experienced by the 

 computing staff in endeavouring to keep pace with the observing, 

 a difficulty which threatens the extinction of our own system of 

 meteorological observations. 



We cannot close this notice without directing attention to the 

 progress of Astronomy in America. Our own National Observatory, 

 under the able management of the Astronomer Eoyal, continues to 

 maintain its position as the most important astronomical establish- 

 ment in the United Kingdom. There is, however, much useful 

 work to be effected by amateurs, who may consult the volume before 

 us with advantage. 



