Notices respecting New Books. 309 



only answer that occurs to us is, that the writer hopes by inserting 

 these matters to render his book accessible to readers who bring 

 nothing with them but a knowledge of the elements of Algebra, 

 Geometry, and Trigonometry. Our author may perhaps find one 

 or two readers capable of makiug out the contents of the volume on 

 these terms, *. e. capable, while studying a distinct subject, of 

 picking up incidentally a knowledge of the Geometry of Curves and 

 Surfaces of the second degree, the principles of the Differential and 

 Integral Calculus, the properties of the Potential, and some thing 

 more than the elements of Quaternions. All but a very few find it 

 necessary to devote their undivided attention to these subjects ; and 

 even then a great amount of illustration is needed to ensure their 

 being firmly grasped ; and we may add that even the few would 

 be the better for going through the usual discipline, though they 

 might possibly do without it. The remarks made by a most com- 

 petent judge in a somewhat similar case* would, we believe, apply 

 to this. A retentive memory and great clearness and precision of 

 thought may (though only in exceptional cases), supersede the ne- 

 cessity of a progressive training. In other cases, should the student 

 attempt to dispense with such a training, he will probably rise from 

 his labours without retaining a single definite conception either of 

 the propositions or their proofs. 



The Moon, her Motions, Aspect, Scenery, and Physical Condition. 

 By Eichaed A. Proctob. Second Edition. London: Long- 

 mans and Co. 1878. 



The appearance of a Second Edition of this work is strong 

 evidence of an increasing interest in Selenographical inquiries. 

 The Moon's distance, size, and motions, which Mr. Proctor treats 

 of in his opening Chapters, have long claimed the attention of astro- 

 nomers ; and of all the triumphs yet achieved, the Lunar Theory 

 stands preeminent. It is of late years that many astronomers have 

 exhibited no little interest in examining the external characteristics 

 of members of the Solar System, seeking from them to obtain some 

 indications of their physical condition ; and those who are interested 

 in our Satellite are turning their attention especially to the external 

 configuration of her globe, with a view, first, to ascertain if any 

 changes occur among the numerous objects diversifying her sur- 

 face, and, secondly, from the observations obtained to endeavour to 

 derive some idea of the forces operating in her interior. To this 

 part of his general subject our author has devoted two chapters — 

 one on the study of the Moon's surface, the other on its condition. 

 These chapters will be read with interest by every student seeking 

 information on the rise, progress, and present state of Selenography. 

 In many respects this edition is an improvement on the first ; and 

 we wish it all the success which the well-earned popularity of the 

 author is likely to obtain for it. 



* Peacock's Life of Young, pp. 31, 101. 



