128 Notices respecting New Boohs. 



observations and drawings of planetary details and other celestial 

 phenomena. For many years he has been a prolific writer in 

 astronomical serials and the Proceedings of learned societies. A 

 work from his facile pen will therefore be read with much interest 

 and expectation by all lovers of the " sublime science." And his 

 readers will not be disappointed. This is a. very interesting and 

 valuable work. Emanating as it does from a distinguished astro- 

 nomer, and founded as it is on the results of the author's practical 

 experience, it is of course worthy of more attention and confidence 

 than books which are merely compilations from the writings and 

 observations of others. 



The book opens with an interesting chapter on the invention 

 and development of the telescope. The second chapter discusses 

 the relative merits of large and small telescopes, in which it is 

 clearly shown that the utility of small instruments is not to be 

 despised. The author thinks that future development in telescopes 

 will take place in the size of reflectors rather than in refractors, 

 which have now nearly reached their limit of aperture, and in this 

 conclusion he is most probably correct. In Chapter iv. most 

 useful hints are given to the amateur observer on telescopic obser- 

 vations, and the best methods of arriving at useful results. Mr. 

 Denning very justly says (p. 78), " Some amateurs take an in- 

 credible amount of pains to look up an object for the simple satis- 

 faction of seeing it. But seeing an object is not observing it. The 

 mere view counts for nothing from a scientific standpoint, though 

 it may doubtless afford some satisfaction to the person obtaining 

 it"; and again (p. 81), "It need hardly be said that every difficulty 

 may be surmounted by perseverance, and that a man's enthusiasm 

 is often the measure of his success, and success is rarely denied to 

 him whose heart is in his work." 



Interesting chapters follow on the Sun, Moon, Planets, and 

 Comets, and contain much information and many useful practical 

 hints. The chapter on " Meteors and Meteoric Observations " is, 

 as might be expected from Mr. Denning, especially good. 



The concluding chapters of the work treat of the Stars, Nebula?, 

 and Clusters. These include some useful tables of some remarkable 

 objects ; but the list of variable stars is rather short, some interest- 

 ing objects — for instance E Leonis — being omitted. In a second 

 edition this list might with advantage be extended to, say, two 

 pages instead of one. 



It is the duty of a reviewer to look for misprints and errors in 

 the book he reviews. Mr. Denning's book has passed through this 

 ordeal very satisfactorily. Of misprints none have been detected. 

 Of inaccuracies there are very few. On p. 114 the moon's mean 

 distance is given as 237,000 miles. This should be 238,800 miles. 

 Mann's orbit for Sirius, referred to on p. 307, is now known to be 

 incorrect. The companion has certainly not yet passed through 

 the periastron, and probably will not do so for a few years to come. 

 In the List of Variable Stars, p. 311, the minimum of o Ceti is 

 given as 0, or complete invisibility even with a telescope. This is 



