358 SCIENCE PROGRESS 



about the nature of reality, and what kind of assumptions it has to make before it 

 tells us anything." It is difficult to find in the volume conclusions which can be 

 described as an approximate and provisional answer to the questions raised. 



There are, nevertheless, a large number of points of interest. In some quar- 

 ters there seems to be a vague impression that there is likely to be founded a 

 new philosophy based on science which will displace philosophy as commonly 

 understood. Ostwald and Mach are the principal writers who commonly appeal 

 to this school. To such, Mr. Broad's volume, and especially the chapter on 

 phenomenalism, can be recommended as an antidote. Although Mr. Broad is 

 in sympathy with the scientific point of view, and acknowledges the philosophic 

 importance of scientific research, he is opposed to a narrow scientific view of 

 philosophy. On the other hand, he emphatically asserts the probability that 

 scientific constructions and hypotheses (such as atoms and electrons) may possess 

 a greater degree of reality than the school of Mach will allow. While such 

 information about reality is not certain, there is no sound philosophic reason for 

 asserting that such constructions are merely conceptual shorthand. In matters 

 like these, Mr. Broad is an admirable advocate of the common-sense view of 

 science. 



It seems inevitable that works dealing with science in its relation to philosophy 

 should devote considerable space to the philosophy of cause. The volume under 

 review is no exception to the rule. The chapters on causation and on the causal 

 theory of perception occupy together more than half the book, and it would be 

 hopeless to attempt to summarise them in a brief review. Nor do the conclusions 

 on the laws of mechanics admit of brief and simple statement. 



The appendix is of more than usual interest. Certain aspects of the Principle 

 of Relativity are criticised, and the author thinks that some mental confusion is 

 involved in this interpretation of experimental data. When robbed of the element 

 of confusion the residuum need worry no one. 



The volume is of considerable merit. It should be mentioned also that the 

 dullness of philosophic disquisition is enlivened with occasional epigram and joke. 



H. S. Shelton. 



X-Rays : An Introduction to the Study of Ro'ntgen Rays. By G. W. C. 

 Kaye, M.A., D.Sc, Head of the Radium Testing Department at the 

 National Physical Laboratory. [Pp. xix + 252.] (London : Longmans, 

 Green & Co. Price 5-y. net.) 



The X-rays appeal to so many different classes of workers that a book which 

 gives a full and at the same time not too abstruse account of all that is known 

 about them at the present time is sure to find a ready welcome. Dr. Kaye's 

 book contains in a very compact compass an immense amount of valuable in- 

 formation, written in a clear and lucid manner, mainly from the physical point 

 of view. It avoids the purely technical and also the more mathematical aspects 

 and brings together a great number of widely scattered important physical 

 researches which have not before been collected in book form. On this account 

 it will find a useful place on the shelves of all those who are trying to keep 

 abreast of modern physical researches. But it should also appeal to medical 

 men and medical students, especially those about to take up the subject for 

 the first time and anxious not to depend for their information on purely trade 

 sources. It is obvious that finality is very far from having been reached even 

 in the methods of X-ray production. It is probable that in the future instead 



