6S6 SCIENCE PROGRESS 



ASTRONOMY 



Celestial Objects for Common Telescopes. By Rev. T. W. Webb, M.A. Sixth 

 Edition, revised by Rev. T. E. Espin, M.A. In two volumes. [Pp. xx 

 + 253 and vii + 320, with numerous illustrations.] (London : Longmans, 

 Green & Co. Price 7s. 6d. net each volume.) 



The volumes under review are a new and revised edition of the well-known work 

 by the late Rev. T. W. Webb, first published in one volume nearly sixty years ago. 

 The present revision has been undertaken by that well-known amateur double- 

 star observer, Rev. T. E. Espin, who has been assisted in the portions dealing 

 with lunar and planetary observations by some of the foremost amateur observers. 

 Thus, for instance, Mr. W. Goodacre has supplied some excellent notes on lunar 

 details and also a new and accurate map of the moon, while Mr. W. S. Franks 

 has contributed an interesting and useful note on the double-star micrometer. 

 Mr. Espin is himself responsible for the revision of the double-star portion. 



The addition of new matter in successive editions has resulted in the size of 

 the book considerably exceeding that of Mr. Webb's original work, so that it 

 almost seems as though the original intention — "to furnish the possessors of 

 ordinary telescopes with plain directions for their use, and a list of objects for their 

 advantageous employment " — has been lost sight of. He desired to point the way 

 to the "inexperienced possessor" of a telescope to the chief objects of interest 

 in the heavens. The addition of a large mass of detailed matter, much of which 

 is not within the range of " common telescopes," rather detracts from this aim, 

 and although it undoubtedly increases the value of the work to the experienced 

 observer, for whom it was not primarily intended, it detracts from its value to 

 the beginner, for whom it was intended. 



It is a difficult matter to graft a large amount of new matter on to an old work 

 without at the same time practically rewriting the whole, if a homogeneous result 

 is to be obtained. The present revision suffers rather badly from this patchwork 

 effect, in some instances Webb's original words being mixed up with added matter 

 with, at times, strange results. There are several instances also where the reviser 

 might with advantage have cut out some of the old matter in favour of more 

 up-to-date information ; for instance, Secchi's classification of stellar types has 

 been almost entirely superseded by the more recent and much more convenient 

 Harvard classification, yet the latter is scarcely mentioned. There still remain 

 one or two remarkable omissions in the work ; thus there is no branch of astronomy 

 in which amateur observers can more readily obtain results of real value, even 

 with very small instruments, than in variable star observations. Yet there are no 

 hints at all as to the method of making such observations and the precautions to 

 be taken. Surely the book would have benefited by the inclusion of such informa- 

 tion at the expense of some of the more detailed matter. 



The reviser is perhaps not altogether to blame for the above defects, as the 

 general lines along which the revision was to be carried out may have been laid 

 down for him. We can, however, hardly excuse him for the rather numerous 

 typographical errors which have remained undetected. Some of these are of a 

 serious nature, as 70 15' instead of y° 15' for the value of the inclination of the 

 solar equator. 



Yet in spite of all that we have said, the fact remains that the book is the best 

 of its kind, and should be in the hands of every amateur observer. Its value has 

 been considerably increased by the present revision, which must have occupied 

 Mr. Espin for a considerable time and have given him a large amount of work. 



