344 



NATURE 



[January 2. 1919 



number of the nitro-groups increase, the com- 

 pounds have a proportionally greater toxicity." 



A useful section deals with the manipulation 

 and working up of the finished explosives, grind- 

 ing, mixing, the filling of shells by plain casting, 

 casting under pressure to increase the density of 

 the charge, and by pressing the solid charge. 



The later chapters are devoted to questions on 

 the use of explosives, the measurement of pres- 

 sures, energy, etc. ; then follows an appendix 

 containing a comprehensive review ol patents 

 (which is supplemented later by a " 1'atents 

 Register"). A short further appendix deals with 

 specifications. This last section is extremely 

 meagre, but possibly restrictions were placed on 

 the author in respect to British specifications, and 

 moreover those handling the materials have to 

 be familiar with the requirements. 



The volume is inconveniently large; much space 

 might have been saved with advantage. For 

 example, graphic formulae are unnecessarily large ; 

 in one instance three formulae almost fill one page ; 

 subdivision into separate chapters where collec- 

 tion under one heading was possible has led to 

 much blank space, and some very simple 

 diagrams have a whole page devoted to each. 



IS PSYCHOLOGY ONE OF THE 



NATURAL SCIENCES? 



Psychological Principles. By Dr. James Ward. 



(The Cambridge Psychological Library.) 



Pp. xiv + 478. (Cambridge: At the University 



Press, 1918.) Price 21s. net. 

 "DSYCHOLOGY, ever held in high honour as 

 -*- a philosophical science, is to-day claiming 

 to be one of the natural sciences. Sometimes it is 

 distinguished as the new psychology. It regards 

 its subject-matter as amenable to treatment in 

 laboratories, and in two directions, one educa- 

 tional and industrial, the other medical and thera- 

 peutic, it appears to have established its claim to 

 be assigned a special realm of scientifically classi- 

 fied facts. 



Since 1884, the year in which Dr. Ward wrote 

 the famous "Encyclopaedia Britannica " article, 

 the output of this new psychology in books and 

 journals and society proceedings has been enor- 

 mous, its variety almost defying classification. 

 It ranges from statistics and correlations to elabo- 

 rate hypotheses of the fundamental nature of the 

 reality of psychical phenomena. Throughout this 

 whole period Dr. Ward's "Encyclopaedia " article 

 has stood almost unchallenged in its authority as 

 the exposition of the principles which must govern 

 every science of the soul. There are only two 

 books which can compare with it in this respect — 

 namely, James's "Principles of Psychology " and 

 Stout's "Manual," and these are' in no sense 

 rivals, for each of the three is unique. Yet we 

 cannot help sympathising with Dr. Ward's disap- 

 pointed feeling that the conditions necessarily 

 attaching to an article in an encyclopaedia arc a 

 serious handicap to its usefulness compared with 

 the unrestricted form of the separate treatise. 

 NO. 2566, VOL. I02] 



At last, however, we are allowed to have this 

 important work in a volume, and the wonderful 

 thing is thai it appears, not as an overdue 

 promise in the fulfilment of which we have lost 

 interest, but as a new work with all the freshness 

 ol youth; and the large additions to the original 



article are not makeshilt appendages, but natural 



de\ elopments. 



\ii one who reads this book 1 an fail to appre- 

 ciate the significant service Dr. Ward has rendered 

 to psychology. It is evident alike in the paths 

 he follows and in those which he avoids as side- 

 tracks, or turns away from as false routes. We 

 are not invited, for example, to begin with a more 

 or less detailed description of the nervous system, 

 and we are therefore spared altogether that illusion 

 which so powerfully influences the psychologists 

 whom it fascinates, the illusion that it is only a 

 little gap in our science, an unfortunate hiatus we 

 have not yet succeeded in bridging, which pre- 

 vents us passing directly from physiology to 

 psychology, from the science of the nervous 

 system to the science of the mind. Again, with 

 a clear conception of its utter futility, Dr. Ward 

 rejects the notion that psychical facts belong to 

 the same order of reality as physical facts, differ- 

 ing from them only in their diaphaneity and 

 elusiveness, but capable of being mathematically 

 treated by cunningly devised psycho-physical 

 apparatus. Dr. Ward's attitude towards such 

 method is shown in a characteristic note in the 

 preface, in which, apologising for the retention 

 of the chapter on " Memorising, Rhythmising, and 

 Reading," originally inserted "by way of illus- 

 trating the so-called new psychology," he adds: 

 " If there is one chapter more than another in the 

 book which may be 'skipped,' it is this." 



The greatness of this book is not in its nega- 

 tions, but in the clear and masterly way in which 

 it sets forth the principles that govern psychology. 

 No development of the science, or possible dis- 

 covery, can affect these. First and foremost is 

 the principle of the unity of the subject of experi- 

 ence with his experience. This is fundamental in 

 Dr. Ward's view, and insisted on in striking 

 arguments and clear expressions. The point of 

 view of psychology is individualistic. Psychology 

 is the science of individual experience. As pre- 

 sented to an individual, "the whole choir of 

 heaven and furniture of earth " may belong to 

 psychology. 



In close connection with this definition of the 

 subject-matter and scope of psychology is the 

 principle of the indissolubility of the subject- 

 object relation in experience, and the insepara- 

 bility of its factors into subjects of experience 

 on one hand, and objects of experience on 

 the other. The subject-object relation is not a 

 dualism of two terms, but a duality in unity. 

 The importance of this principle in regard to the 

 Status of psychology as a science can he easilv 

 seen. In the physical sciences we select among 

 the objects of experience special groups and 

 classes and treat them on the assumption that 

 they are in their essence what they are known t< 



