44© 



NA TURE 



[September 30, 1922 



convincing could be adduced in illustration of the 

 necessity for a working co-operation between the 

 physicist and the engineer. Sir Alfred Ewing recently 

 defined engineering as " the turning to man's use and 

 convenience of the things which it is the business of 

 physics to understand." This Dictionary helps one 

 to realise, as perhaps never previously, that in all 

 branches of engineering the engineer, whether reveal- 

 ing or directing, whether inventing or designing, 

 whether testing or measuring, whether systematising, 

 co-ordinating, or clarifying, is continually turning 

 physical principles to account. 



Sir Richard Glazebrook, not content with the endur- 

 ing monument to his fame in the shape of the National 

 Physical Laboratory, has now laid physicists and en- 

 gineers under perpetual obligation by undertaking the 

 editorship of this " Dictionary of Applied Physics." 

 No other British man of science, it is safe to say, could 

 have brought the same wide experience, intimate 

 knowledge, and critical judgment to bear upon the 

 production of an encyclopaedic work of this nature. 

 For twenty years Sir Richard Glazebrook directed the 

 policy of the N.P.L., and during that period, when the 

 attitude of the nation towards scientific investigation 

 was very different from what it is to-day, he toiled 

 unceasingly to foster the applications of science to 

 industry. To take one example alone, the fact that 

 this country in 1914 led the world in aeronautical re- 

 search is due in no small measure to his foresight and 

 skilful guidance during the preceding eight years. Sir 

 Richard's breadth of interests and his habit of estab- 

 lishing and preserving personal contact with original 

 investigators are reflected in his choice of collaborators 

 in the preparation of this Dictionary. 



The work under review is the first of a series of five 

 volumes, planned to cover the entire range of physics 

 and, in particular, the applications of physics to 

 industry. Volume 1 contains some fifty articles, 

 covering mechanics, engineering, and heat. 



Three main facts emerge from a survey of the work 

 before us — first, the unexampled wealth of material ; 

 secondly, the authoritativeness, the maturity of 

 judgment, the originality and inviting freshness of 

 treatment which are exhibited by the majority of the 

 writers ; and, lastly, the presumption and futility of 

 any single reviewer attempting to appraise such a 

 diversity of articles by such a galaxy of experts. A 

 glance at the names of contributors furnishes sufficient 

 guarantee that the various subjects are dealt with by 

 accepted authorities and experienced investigators ; 

 and probably the only useful service that a reviewer 

 can hope to perform is to point out a few of the sins 

 of omission which are inevitable in a treatise planned 

 on such a comprehensive scale. 

 NO. 2761, VOL. I io] 



The first article in the volume is on air pumps, by 

 the staff of the General Electric Co., and deals with 

 the fundamental principles of the various types of 

 pumps employed for evacuation and compression. 



Calorimetric measurements are dealt with in a series 

 of five articles by Dr. Ezer Griffiths. The subject is 

 divided into sections dealing with bomb calorimetry, 

 electrical methods of calorimetry, method of mixtures, 

 methods based on change of state and the applications 

 of the quantum theory to specific heat data. A glance 

 through these articles shows how different are the 

 methods employed by research Workers from those 

 described in text-books on this subject. As an indica- 

 tion of the highly developed state of technical calori- 

 metry, it might be mentioned that with one of the 

 bomb-calorimeter equipments described — that of the 

 U.S. Bureau of Mines — a skilled operator can average 

 thirty-five determinations per day of the calorific 

 value of fuels. The purely scientific aspect of the 

 subject is not neglected, for we find concise descriptions 

 of the researches of White on specific heats at high 

 temperatures and those of Dewar at low temperatures. 

 Electrical methods of calorimetry naturally occupy a 

 prominent place, for the ease with which electrical 

 energy can be measured and controlled has placed a 

 powerful tool in the hands of workers concerned with 

 thermal measurements. 



The principles of dynamical similarity are discussed 

 in an article by Dr. H. Levy. The results of wind- 

 channel and ship-tank experiments on models can be 

 applied to full-scale machines by the use of the Prin- 

 ciple of Similitude, which also finds application in 

 numerous other branches of engineering. One is re- 

 minded of a famous article by the late Lord Rayleigh 

 in Nature, vol. 95, p. 66, 191 5, in which the full gener- 

 ality and beauty of the Principle of Similitude are 

 brought out. In the space of a column or two Rayleigh 

 deduced a series of fundamental conclusions with the 

 lucidity and brevity which distinguish all his writings. 



Four articles are devoted to various aspects of steam 

 engineering. Sir Alfred Ewing contributes one on the 

 theory of the steam engine ; Mr. A. Cruickshank 

 another on the reciprocating steam engine, while the 

 importance of the steam turbine fully merits the 

 38 pages devoted to the two articles on the physics 

 of the steam turbine by Dr. Gerald Stoney and Mr. 

 Telford Petrie, and the development of the steam 

 turbine by Mr. R. Dowson of Messrs. Parsons. 



These articles cover the ground pretty thoroughly, 

 so far as present-day practice goes, but one would have 

 liked to know something of the writers' views on the 

 future trend of their subjects. For example, nothing 

 is said of the possibilities of the gas turbine, should the 

 practical difficulties connected with it be overcome, or 



