September 8, 1923] 



NATURE 



35 



chief characteristics of the age we Hve in. Even in 

 England it is sufficiently striking, but in the United 

 States one person in every ten, man, woman, and 

 child, has an automobile ; an average of one to every 

 alternate household. Even so the continued output of 

 the Ford factory is measured in thousands of cars per 

 day. America may be a land of wide spaces, but if 

 this rate should continue it is not difficult to foresee a 

 further field for the activities of "control" societies, 

 this time aiming at control of the Ford " birth rate." 



The growth of road transport was not due to the 

 stimulus of the War : it was in full steady growth 

 before 1914. But in the case of aviation, the future 

 of the aero-engine as a prime mover is, and must be, 

 vitally affected by the stimulus which grew from the 

 War and still continues. During the War itself the 

 best scientific and engineering talent was encouraged 

 by every possible facility, and by lavish outpourings of 

 money, to produce yet newer and newer developments 

 of the internal combustion engine — whether for aviation, 

 tanks, seagoing craft, or road transport ; but chiefly 

 for aviation. Aviation offered then a prospect of a 

 way out from what seemed an endless deadlock ; people 

 had begun to fear that in the great struggle, there 

 had unconsciously been invented a new, and very 

 unpleasant, way of life. Since then a relatively im- 

 poverished world has sought to find less costly means of 

 defence than the old ; and the public, led doubtless by 

 the results of certain American experiments, has begun 

 to look towards the relatively cheap defence by air- 

 craft as affording a loophole for escape from financial 

 burdens which might threaten to become overwhelming. 

 As a mere business proposition, therefore, it " pays " 

 to encourage aviation, and the surest path of progress 

 in this sense lies in the development of improved aero- 

 engines which shall be of unprecedented power, of 

 extreme lightness, and yet be able to operate with 

 equal facility at any altitude and at any temperature. 



One of the pioneers in this necessary development 

 of the internal combustion engine is Mr. Ricardo. 

 We reviewed some little time back the first volume 

 of his book (Nature, January 13, p. 43). That 

 volume dealt mainly with the older slow-speed 

 engine. The second volume is concerned with the 

 high-speed engine and with its utilisation for certain 

 specialised purposes. It is a fine record of scientific 

 research work ; carried out in no small measure by Mr. 

 Ricardo himself, or by those with whom he has been 

 associated, directly or indirectly, through the medium 

 of the Aeronautical Research Committee. 



We are well acquainted with most of the books on 

 this subject which have appeared during say the last 

 twenty years, and it is striking to reflect on the change 

 in the point of view shown by the writers at the begin- 



NO. 2810, VOL. 112] 



ning of that period and at the end. If Mr. Ricardo be 

 taken as typical of the modern writers, and to do so is to 

 pay them compliment, it will be seen from even a 

 cursory survey of the present volume that nothing, 

 however traditional in the art, is taken for granted. 

 Each problem is stated in scientific language, and 

 critically and dispassionately examined : very often 

 the results are unexpected, but whether strange or not, 

 this critical review of them has the immense merit 

 that a chain of possible causation is constructed to 

 which new links can be added, by those who have 

 scientific imagination and insight, leading to new lines 

 of development. Each piece of analysis in fact is made 

 to carry within it the germ of the next step forward. 



The mere bulk and weight of Mr. Ricardo's two 

 volumes is forbidding, and might with advantage have 

 been lessened. That, however, is probably more a 

 matter for the publishers than the author. The author 

 has done his part of the work well, though the book 

 would certainly have gained by the freer use of the blue 

 pencil. We have found very few mistakes, though the 

 puzzling letter-press associated with figure 33 on p. 121 

 does not seem to us to make the carburation procedure 

 represented intelligible to the average reader. 



Mr. Ricardo is evidently not satisfied with the present 

 position as to fuel supplies. As is well known, much of 

 his own research work has been devoted to fuel questions 

 — his investigations for the Asiatic Petroleum Company 

 he has fortunately been in a position to make public : 

 much to the credit of that firm. We quote from the 

 present volume : " The mobile internal combustion 

 engine is now no longer a luxury ; it has become one of 

 the prime necessities of peaceful civilisation and the 

 prime necessity in time of war ; therefore, the assurance 

 of its fuel supply should be considered a matter of 

 national importance. It is perfectly well known that 

 alcohol is an excellent fuel, and there is little doubt that 

 sufficient supplies could be produced within the 

 tropical regions of the British Empire, yet little or 

 nothing is being done to encourage its development." 

 It must be remembered, however, that although plants 

 well suited for the production of alcohol are easily 

 grown in, say, tropical British Africa, it is likely to 

 be a costly matter with present facilities to collect 

 and deal with the material on the spot; hence it is 

 reasonable that a very strong case should be put up by 

 the engine users before steps are taken to embark on 

 large schemes for power alcohol production. 



Lest it should seem that the high-speed engine is 

 being considered too exclusively and the older engine 

 ignored, Mr. Ricardo puts his view on record : " That 

 the internal combustion engine has found its ultimate 

 sphere in the light mobile high-speed type is now 

 evidenced by the fact that, whereas in the years 



