300 Xoticcs respecting New Booh. 



only the first of the remarks of this paper, viz. that of art. 1, 

 finds here application, — and this also apparently 'with some- 

 what diminished arithmetical import, owing to the change in- 

 stanced above as second. It might be stated, on the other hand, 

 as noteworthy, both in this last and the former research, but 

 more especially the first-mentioned, that no more equations 

 "were employed for determining the constants of the empirical 

 formula?, by which the result of the whole investigation ought to 

 be embodied, than what are strictly necessary for the purpose ; 

 so that in the latest example, of from eight to eleven measure- 

 ments separately performed for each gas, only three on the whole 

 do any practical duty in each case. 

 Oxford, February 1863. 



XLI. Notices respecting New Books. 



On Matter and JSther, or the Secret Laws of Physical Change. By 

 the Rev. Thomas Rawson Birks, M.A. Cambridge: MacMil- 

 lan & Co., 1862. 

 TT might be questioned whether this work ought to receive any 

 ■*■ notice in a scientific Journal, the character and contents of it 

 being such that it can hardly be permitted to take rank among scien- 

 tific productions. It is, in fact, singularly deficient in one particular, 

 which has hitherto been considered essential in theoretical physics, 

 namely, the development of the results of assumed principles by 

 means of mathematical reasoning. As, however, advantage may be 

 derived from the scrutiny of a false or defective way of philosophizing, 

 we have thought it worth while to bring the work under review, 

 especially as the too confident tone in which it is written may gain 

 for it, among readers not qualified to judge of its contents scienti- 

 fically, an influence which may need to be counteracted. It is cer- 

 tainly a very readable book, and embraces a great variety of scien- 

 tific facts, for the most part clearly and correctly stated ; for which 

 reasons there is the more necessity for pointing out its radical faults. 

 In page 10 there is a quotation from Newton's ' Principia,' intro- 

 duced with this remark : — " The closing words of the ' Principia ' are 

 like a prophecy, and show in what direction the second main series , 

 of physical discovery must be attained." We quite agree with this 

 estimate of the passage referred to, which, together with one quoted 

 in the next page from the ' Optics,' may well be regarded as wonderful 

 evidence of Newton's genius and foresight. To make intelligible the 

 subsequent criticisms it will be proper to adduce both these passages. 

 The one from the 'Principia' is as follows : — " I might add something 

 about a certain very subtle spirit which pervades dense bodies and lies 

 hid in them ; by the force and agency (vi et actionibus) of which, 

 bodies at very small distances attract each other, and when brought 

 close together, cohere ; and electrical bodies act at greater distances, 

 both repelling and attracting neighbouring bodies ; and light is 



