154 SCIENCE PROGRESS 



Unfortunately it is impossible to take quite the same favourable view of the 

 manner in which the fundamental principles have been treated. It must be 

 remembered that, in the great majority of cases, the intermediate course furnishes 

 the only training in pure science that the engineer receives. It becomes, there- 

 fore, even more important in his case than in that of the chemist or physicist to 

 give some insight into methods of scientific thought and to attempt to inculcate, 

 if only by example, something of the spirit and inspiration of science. It is 

 essential to impart some knowledge as to how and why the governing principles 

 originated and developed ; of the difficulties overcome and remaining to be solved ; 

 and above all of the theories, however incorrect they may ultimately prove to 

 be, by which we endeavour to connect our ideas. In this way science is realised 

 as a living organism ; facts are seen in their several aspects ; the imagination is 

 stimulated and the mind is brought into touch with the hidden processes of nature, 

 whose external effect alone it is usually possible to study. No doubt these things 

 are not essential for success in examinations or for the acquirement of a consider- 

 able facility in working routine problems, but they form a very necessary part of a 

 true scientific equipment. 



Judged from this standpoint the book is far from satisfactory, as a few examples 

 will suffice to show. On the first page there is this statement : "The fundamental 

 units — to which are referred all measurements in any scientific system — are those 

 of length, mass, and time." That is all that is said about them. The student is 

 not invited to stop and think why such units are required, why there are only 

 three, why this particular three, or of the possibility of choosing others. Again, 

 mass is defined simply as " quantity of matter." It is not discussed at all, and 

 there is not the vaguest suggestion as to how it can be measured apart from 

 weight. Such teaching can only be characterised as shallow and vague. Apart 

 from three pages containing a specially uninteresting and uninformative account 

 of the kinetic theory of gases, there is no mention at all of the kinetic theory of 

 matter, so that in dealing with thermal conductivity, after stating that the heat " is 

 passed through from layer to layer " of a body, the authors are compelled to say 

 that " the process has not yet been investigated thoroughly." True, the exact part 

 played by the electron in the process is uncertain, but in these days of low-tempera- 

 ture research, Brownian motion, and the revelations of the X-ray spectrometer, it is 

 not unreasonable to expect something a little more satisfying. The definition of 

 conductivity in terms of the heat flowing through a unit cube is usual, but none 

 the less objectionable. Convection is treated in the old-fashioned way as a 

 separate mode of heat transfer instead of a case of accelerated conduction. On 

 the other hand, in the section on thermodynamics there is a genuine attempt to 

 explain what is meant by a reversible cycle. Kelvin's absolute temperature scale 

 is given again ; it is never really understood by elementary students, and, being 

 quite unnecessary, might well be relegated to the advanced course or, better still, 

 to the historian. 



The other sections of the book are less open to criticism. In giving the 

 Young- Helmholtz colour theory it should be pointed out that, successful as it has 

 been in connecting many of the phenomena of colour vision, it is nevertheless now 

 known to be incorrect. In the account of the theory of electrolysis the all- 

 important fact that the charge on a monovalent ion is equal to that on an electron 

 is not mentioned, and, indeed, there is no attempt at all to give the reader any 

 notion of the mechanism of the electric current. Electrostatics is placed most 

 remarkably in the middle of current electricity. 



With the exception of the first part (dynamics) the book can safely be recom- 



