Literary Notices. 455 



We have thus endeavoured to show that the formal law 

 which appears best to represent celestial phenomena, asserts 

 that the approach of two heavenly bodies produces light. Now 

 what physical cause does this imply ? It has been remarked 

 by the writer, in conjunction with Professor Tait, that we are 

 not without an analogous law in another branch of science, for 

 we know that the approach of two atoms towards one another 

 also produces light. Again, is it not conceivable that the law 

 indicated in this paper may be merely that arrangement by 

 means of which the visible motion of bodies is converted into 

 light and heat, which we know, from Professor Thomson, are 

 the ultimate forms to which all motion tends. This problem is 

 one of great interest, but it can only be solved by laborious 

 observation. 



LITERARY NOTICES. 



Outlines of Astronomy. By Sir John F. "W". Herschel, Bart., 

 K.H., etc., etc. Seventh Edition (Longmans). — There are very few 

 scientific works that can compare with Sir John Herschel's well 

 known " Outlines of Astronomy," as a masterly exhibition, not only 

 of the fundamental facts, but of the methods of reasoning in the 

 higher branches of physical inquiry. Many writers have succeeded 

 in giving intelligible explanations of the principal astronomical 

 laws, and of the results to which they give rise ; but we could name 

 no book equal to the " Outlines," in its capacity of making physical 

 science an aid to a vigorous and yet pleasurable training of the 

 mind. The leading facts aud principles of Astronomy remaining 

 unchanged, that which was well said concerning them when the 

 first edition of Sir John Herschel's work left the press, is equally 

 applicable now that the seventh edition appears in answer to public 

 demand ; but still there are some departments, in which recent 

 researches have unfolded new truths, that require more notice 

 than they have received in the volume before us, which is very 

 little more than a reprint of the last edition. If Sir John Herschel's 

 age and engagements prevented his paying due attention to the 

 views concerning the constitution of the sun, which have been 

 unfolded by the application of the spectroscope, and by considera- 

 tions resulting from the mechanical theory of heat, and to other 

 recent speculations and observations, it would have been Avise to 

 have transferred the task of bringing out a new edition of his 

 famous work to his son Alexander, who has displayed scientific 

 capacities of no common order, and bids fair to be known to 

 posterity as the third of his illustrious name. But although we 

 thus express a wish that we had been favoured with a little more, 

 that which Sir John again offers to us is essential, and nowhere 

 else presented equally well. 



