REVIEWS 501 



instructions, is a really good epitome of shop practice, though of course 

 other methods than some of those laid down have their advocates. Those 

 who in the early days of aviation had to find out their rules of construction 

 by trial will best appreciate how easy it is, up to a point, to become a designer 

 nowadays. Beyond that point the best brains are still required. 



The mechanical production of the book is of the highest quality as to 

 printing, diagrams, and mathematical symbols. 



The use of heavy type for emphasis is not always happy, and might be 

 restricted with advantage. 



A. R. L. 



Electrical Engineering. By T. F. Wall, D.Sc, D.Eng., A.M.Inst.C.E., 

 A.M.I.E.E. [Pp. xi + 491, with 463 diagrams and illustrations.] 

 (London: Methuen & Co., 1921. Price 21s. net.) 



Every author of a text-book on electrical engineering seems, in wTiting the 

 book, to have an aim and object which, at least in his opinion, differentiates 

 his work from all the other and numerous textbooks that have already been 

 written on the subject. The author of the volume under review is no exception 

 to this generalisation, although his chief object in writing the book — viz. 

 " to give a survey of the principles of electrical engineering which shall be 

 as complete as possible in one volume of moderate size " — is one which is 

 doubtless in the mind of every writer on this branch of engineering. 



To what extent he has succeeded in following his aim, may perhaps best 

 be judged from a brief resume of the contents of the book. It is divided into 

 six sections, each of which is more or less complete in itself, and deals with 

 one of the fundamental divisions of the subject. These are : I. Static 

 Electricity; II. Magnetism; III. Direct-Current Elecricity ; IV. Electro- 

 Magnetism ; V. Alternating Currents ; and VI. Units. These sections 

 contain chapters dealing with the following subjects : First Principles ; 

 Some Deductions from Coulomb's Law of the Force between Electrified 

 Particles ; Potential-Capacity ; the Dielectric and the energy of the electric 

 field ; Electrical Machines and Electrometers ; Coulomb's Law of the Force 

 between Magnetic Poles ; Magnetic Induction — Magnetic Properties of Iron 

 and Steel — Effects of Temperature on Magnetisation ; Diamagnetic Sub- 

 stances — Permanent Magnets ; The Earth's Magnetic Field ; Electric Resist- 

 ance ; Electrolysis ; Electric Accumulators ; Thermo-Electricity ; Magnetic 

 Effects of Electric Currents ; Electromagnetic Induction ; Galvanometers, 

 Fluxmeters, Oscillograph, Wattmeters, Ammeters, Voltmeters, Frequency 

 Meters ; Single, Two, and Three Phase Alternating Current Systems ; 

 Harmonic Analysis ; Magnetic Fields due to Alternating Currents ; Use of 

 Complex Quantities in A.C. Problems. 



Although grouping together of the elementary with the advanced, of the 

 introductory with the more specialised, will doubtless appeal strongly at the 

 present time to the student's pocket, it is open to debate whether such a 

 course is a wise one. More than half of the volume is devoted to the earlier 

 sections on the fundamentals of electricity and magnetism, and to the parts 

 of the subject which belong almost more properly to the elementary physics 

 laboratory than to the electrical engineering lecture room, so that the serious 

 engineering student will still require further and more specialised books to 

 help him over the later stages of his work. The general appearance of the 

 book savours of a mathematical treatment of the subject, although in no 

 case is this treatment unduly difficult ; but, at the same time, it seems of rather 

 doubtful utility to the student to discuss these elementary portions in terms 

 of the integral calculus. The average university student takes his electrical 

 and mathematical courses at the same time, and will not reach a useful stage 

 in the calculus until he has dipped fairly deeply into electrical work. 



