500 Reviews. [ Oct., 
Theoretical Astronomy, relating to the motions of the heavenly 
bodies, &c., embracing a systematic derivation of the formule for 
the calculation of the geocentric and heliocentric places, for the 
determination of the orbits of planets and comets, for the correction 
of approximate elements, and for the computation of special perturb- 
ations ; together with the theory of the combination of observations, 
and the method of least squares, with numerical examples and 
auxiliary tables. By James C. Watson. Royal 8vo, cloth, pp. 662. 
Philadelphia, 1868. Triibner and Co. 
This is a useful treatise, goimg over the same ground as Chau- 
venet’s valuable Treatise on Astronomy. The latter work is, however, 
the more complete. We notice also some pages in Mr. Watson’s 
work which require revision. On the whole, however, and con- 
sidering the extent and difficulty of the subjects treated of, his work 
is a meritorious one. 
Celestial Objects for Common Telescopes. By the Rev. T. W. 
Webb, M.A., F.R.A.S., Incumbent of Hardwick, Herefordshire. 
Second edition, revised and enlarged. Longmans. 
We are glad to see a new edition of Mr. Webb’s valuable treatise. 
As a convenient text-book for the advanced amateur observer, this 
work is likely to hold its ground for many years. In the new 
edition Mr. Webb has availed himself of the advice and experience 
of our leading astronomers. He is himself also in the front rank 
among observers, a circumstance which largely enhances the value 
of his work. His treatise is especially valuable for those who wish 
to take part in the investigation of the moon’s surface. We notice 
a new appendix, in which all the chief lunar objects are arranged 
alphabetically. There are also two other new appendices; one 
containing a list of objects in the southern hemisphere, the other 
giving in their order of right ascension all the stars referred to mm 
the body of the work. There are also one or two new illustrations 
in the present edition. Altogether the work is one which we can 
cordially recommend to all those who wish to become systematic 
observers of the heavens. 
