Notices respecting New Books. 233 



ferent result was produced, but await without anxiety " the judg- 

 ment;and decision of mathematicians" which Prof. Young invokes, 

 and have the honour to remain, 

 Gentlemen, 



Your obedient humble Servant, 



J. J. Sylvester. 



XXX. Notices respecting New Books. 



Saturn and its System. By Richakd A. Proctor, B.A., late Scholar 

 of St. Johns College, Cambridge, and King's College. 8vo. pp. 252. 

 London : Longman and Co. 1865. 



ri^HIS work contains a popular account of all the points of inter- 

 -** est to be met with in the course of a detailed study of the 

 motions and appearances of the planet Saturn. Of course, when 

 any astronomical work is termed popular, no more is intended than 

 that it can be understood by persons acquainted with the elements 

 of geometry and mechanics. In this sense a work is called popular 

 when it expounds methods and states results, but does not aim at 

 applying the methods to the determination of the results. To read 

 such a work requires a considerable expenditure of thought and 

 attention, but not a special scientific training, it is therefore addressed 

 to that large and intelligent class which has been not inaptly termed 

 the " scientific laity." Perhaps the best example of such a popular 

 work is Sir J. Herschel's * Outlines of Astronomy ' — a work which, 

 as is well known, makes serious demands on the reader's attention, 

 though it can be read by any ordinary well-educated man who will take 

 the necessary trouble. To the same class belongs the work before us, 

 and a very favourable specimen of the class it is. Mr. Proctor first 

 considers the simpler elements of Saturn's orbit, and explains how, 

 from its observed motions, these could be determined by astrono- 

 mers furnished with imperfect instruments, but acquainted with the 

 fact that the Sun is the centre of the planetary world. He then 

 proceeds to consider the determination of Saturn's orbit considered 

 as an ellipse, and to trace historically the course of the discovery of 

 the ring, the satellites, and the other phenomena disclosed by tele- 

 scopic inspection. He next investigates with considerable minuteness 

 the changes in the planet's appearance as it describes its orbit, in 

 consequence of the inclination of the plane of its rings to that of the 

 ecliptic. These form the subject of the first four of the seven chap- 



never to argue (in the hope of convincing them of their error) with those 

 suffering under any of these forms of mental hallucination, for I know it 

 would be labour thrown away ; nor do I see reason to follow a different 

 course on the present occasion. I shall be happy to forward a copy of 

 the syllabus of the lecture which has drawn forth Prof. Young's ire to any 

 one taking an interest in the subject. 



