502 SCIENCE PROGRESS 



As a reference book to the student who is finishing his course, as well as 

 to the electrical engineer, the book should prove distinctly useful, since it 

 sets out clearly the underlying principles of the subject, and the manner 

 in which the more advanced portions are built up on them — details which 

 are often apt to be forgotten in the later stages. One might pehaps wish 

 for a somewhat more detailed treatment, with practical details, in parts ; 

 but every work must necessarily have its limitations in some directions. 

 The diagrams are good, and the book has been well prepared and printed, 

 while it is not over encumbered with historical references which merely 

 clog up the main subject. 



Philip R. Coursey. 



Wireless Telegraphy with Special Reference to the Quenched Spark System. 



By Bernard Leggett, A.M.I.E.E. [Pp. xv + 485, with 230 plates 

 and diagrams.] (London: Chapman & Hall, 1921. Price 30s. net.) 



As the author states in his Preface, the literature of radiotelegraphy pub- 

 lished in English has in the past been lamentably lacking in anything more 

 than mere outlines of the Quenched Spark " system," whereas it has dealt 

 in exienso with other types of apparatus. The present work attempts to 

 overcome this deficiency by presenting a textbook of Wireless Telegraphy 

 and Telephony with particular reference to quenched spark apparatus. The 

 reason for the aforementioned deficiency is not hard to find — and is probably 

 due to at least two main causes : firstly, the commercial interests of the 

 leading English wireless company, which were directed in other channels ; 

 and, secondly, national prejudice against a " system " that not only originated 

 in Germany, but received practically the whole of its development in that 

 country — or, at least (and what is practically the same thing) , under German 

 engineers working in other countries. What development work has been 

 carried out here has received little publicity in English, not only for com- 

 mercial reasons, but mainly because, outside of the ordinary electrical press, 

 this country, until quite recently, possessed no technical radio journal in 

 which such work could be chronicled. 



Although quenched spark apparatus has now been adopted extensively 

 in many countries, and adapted to the needs of several different wireless 

 companies, it may be noted that, with the exception of certain British Army 

 apparatus developed by the Signals Experimental Establishment during 

 the war, the bulk of the instruments described and illustrated in this book 

 are of Telefunken design — so that the volume really accomplishes little 

 towards dispelling the all-prevalent opinion as to the Teutonic nature of 

 the whole " system." 



The just criticisra levelled in this book against most British pre-war 

 literature as to its biassed view-point cannot unfortunately be removed from 

 the present work, since the author apparently holds the opinion, shared 

 by many other writers in the radio sphere, that the particular " system " 

 with which he is most familiar is the only one that is of much use at all for 

 practical work. It would seem that the perfectly impartial, and at the 

 same time comprehensive, wireless textbook has yet to be written. In 

 common, too, with many other writers on similar subjects, the author 

 appears to be well informed as to the latest developments of the company 

 with which he is, or has been, connected, but appears to be very much out 

 of touch with the doings and general practice of other companies. Some of 

 the comparisons drawn under these conditions are perhaps, therefore, not 

 altogether justifiable. 



The author states that the work under review has been compiled from 

 a series of technical notes taken over a period of several years. It is prob- 

 ably as a consequence of this that the treatment is in some cases somewhat 



