Notices respecting Neiv Books. 399 



weight," when he so rigidly insists " that there is nothing abso- 

 lute or unconditioned in the world of reality," is by no means clear, 

 especially as we find from the context that what he calls " absolute 

 weight " is evidently and, indeed, necessarily based upon a relation. 

 In any sense the expression "absolute weight" is a contradiction 

 in terms. From this the author argues that " the ordinary state- 

 ment of the fact is crude and inadequate;" and adds that it is 

 " further necessary to remember that this weight may be infinitely 

 reduced, without any diminution in the mass of the body weighed, 

 by a mere change of its position in reference to the body between 

 which and the body weighed the relation subsists." It is this very 

 constancy of mass or quantity of matter amid all changes, of ne- 

 cessity relatively determined, which chemists mean to indicate 

 by the expression " indestructibility of matter ;" and the author's 

 criticism merely amounts to a quibble about words ; he has mis- 

 taken the letter for the spirit. Of the second half of the volume, 

 Chapters IX. to XII. are devoted to the theory of Cognition, and 

 contain an analysis of scientific ultimates, Matter, Force, Time, and 

 Space — that is, a consideration of how we really know these, to 

 what realities these words correspond. This being not strictly a 

 scientific inquiry, although of much interest and importance, the 

 results will not be considered here. In Chapters XIII. and XIV . 

 transcendental geometry receives most serere and lengthy treat- 

 ment. Lobatschewsky's non-Euclidean geometry and Niemann's doc- 

 trine of the manifoldness of space, which have occupied the attention 

 of the most eminent mathematicians during recent years, are consi- 

 dered to be absurd. The same ontological error " which has given 

 rise to the atomo-mechanical theory in physics, has led to the doc- 

 trine of pangeometry in mathematics." Even admitting the author's 

 criticism as to the nature of space, it by no means follows that trans- 

 cendental geometry is not a legitimate department of mathematics. 

 The Nebular Hypothesis is considered in Chap. XV. as the cosmogony 

 of the atomo-mechanical theory. The author rejects the hypothesis, 

 first, because "all speculations respecting the universe as an unli- 

 mited whole " are fundamentally inadmissible ; and, secondly, the 

 hypothesis has proved to be at variance with a number of impor- 

 tant astronomical facts. The last chapter of the book consists of 

 a summary and forecast, the author concluding that " the atomo- 

 mechanical theory cannot be the true basis of modern physics," and 

 looking to the Conservation of Energy as a basis for the future. 



On the whole the book deserves careful consideration from all 

 physicists ; for although the author has more than once mistaken 

 the letter for the spirit, which gives some of the criticism a ludi- 

 crous aspect, and, further, has in many cases attributed to Science 

 speculative doctrines aud opinions held by individual scientific men, 

 yet there is much acute and careful critical work in the volume. 

 Certainly Science ought to be the first to welcome and the last to 

 reject candid criticism of her methods and theories ; for, perhaps 

 even more than other pursuits, Science maintains Magna est Veritas 

 et prcevalebit. Wtistdham K>. Ditnstaf. 



