Notices respecting New Books. 303 



are perfectly comprehensible by the commonest experience, and it is 

 this very circumstance that gives reality to the scientific erection that 

 may be reared upon it. 



But it is not because Mr. Birks's views are opposed to Newton's, 

 and cannot, therefore, be considered as making any advance in the 

 direction which Newton indicated, that we hesitate to call his work 

 scientific. Other writers of the present day have equally disregarded 

 Newton's authority ; for, in fact, in matters of science there is no 

 such thing as absolute authority. It may therefore be conceded to 

 Mr. Birks that he is able by a kind of intuition to perceive that each 

 monad of matter forms an indissoluble union with a monad of Esther. 

 But when from this beginning he goes on to account for a great va- 

 riety of physical facts, which he appears to do with much facility and 

 confidence, ordinary individuals will ask to be conducted to the conclu- 

 sions step by step. The intuition which may serve him will not serve 

 them. There is a recognized method by which a philosopher whose 

 perception of physical causes is in advance of that of his contempo- 

 raries can compel assent to his views, and make them common 

 property, — the method of reasoning by symbols, and by the formation 

 and solution of simple and differential equations. Newton's principles 

 of Natural Philosophy were mathematical principles, and his mathe- 

 matics of the highest order for the time. Nothing short of the In- 

 telligence which framed the Universe can dispense with such means 

 of ascertaining the causes of phenomena. It is scarcely credible 

 that a mathematician in these days should have written a book which 

 pretends to give explanations in the whole range of physical science, 

 without introducing a single differential equation. This is showing 

 a disregard of methods that have been generally thought to be indis- 

 pensable, which on no ground can be justified. We suspect that if 

 Mr. Birks attempted to transfer his thoughts into symbolic language 

 for the purpose of tracing consequences by the aid of mathematical 

 reasoning, he would begin to see the magnitude and difficulty of the 

 task he has undertaken. This radical defect in the work, which ex- 

 cludes the possibility of deciding whether or not the explanations it 

 offers are purely imaginary, obliges us to pronounce ittobe unscientific. 



In order to show that these strictures are not made without good 

 reason, it may suffice to adduce one specimen of the author's mode 

 of accounting for natural phenomena. To explain the chemical pro- 

 duction of heat he writes (p. 109) as follows : — 



"The present hypothesis, I believe, provides a full and complete 

 explanation. Heat is simply atomic or molecular vis viva. Sensible 

 heat depends on the oscillations of the solid atoms, transferred through 

 the repulsion of their constituent or adjacent aether to neighbouring 

 atoms, and producing vibrations which can radiate freely through air 

 or in vacuo, like the waves of light. Heat of fluidity consists in the 

 vis viva of each atom in revolving on its own axis of greatest moment, 

 whereby the polarity of neighbouring atoms is weakened or destroyed. 

 Heat of vaporization consists in the vis viva spent or absorbed in 

 removing the chemical atoms to a greater mean distance beyond the 

 limit of maximum cohesive power, so^that the centrifugal force is 



