520 SCIENCE PROGRESS 



a dentist twice a year, loving the " whole," frequently washing 

 one's hands, and not being obstinately stupid. 



The British Journal of Psychology for October 191 8 prints 

 several contributions to a Symposium at a Joint Session of the 

 British Psychological Society, the Aristotelian Society, and the 

 Mind Association, on the subject " Why is the ' Unconscious ' 

 Unconscious?" The discussion was opened by Capt. Maurice 

 Nicoll, who followed the doctrines of Jung, in their more meta- 

 physical aspect. He was opposed by Dr. W. H. R. Rivers and 

 by Dr. Ernest Jones, the latter of whom likewise contributes 

 an article on "The Theory of Symbolism." An interesting 

 article is contributed by Prof. Carveth Read on " The Mind 

 of the Wizard," in which he endeavours to account for the hold 

 made by superstition on primitive peoples. 



Finally we must allude to Prof. James Ward's Psychological 

 Principles, in which that well-known writer greatly expands 

 and renders in a permanent form his famous article on " Psycho- 

 logy " in the Encyclopaedia Britannica. The work is probably 

 the most important contribution to psychology of recent years, 

 though it pays little attention to many of the more modern 

 lines of inquiry, and approaches the subject rather from the 

 purely psychological than from the physiological standpoint. 



MATHEMATICS. By Philip E. B. Jourdain, M.A., Cambridge. 



For the sake of brevity in the following account, which aims 

 at some completeness, we will refer, for those papers which 

 have not been examined at first hand and which seem to be 

 important, to the last part of the Revue Semestrielle des Publica- 

 tions Mathematiques (191 8, 26 [2]), which is supposed to contain 

 references, titles, and often short accounts of all papers in 

 pure and applied mathematics published between October 

 191 7 and April 191 8. Thus, when a man's name in what 

 follows is followed merely by a number enclosed in parentheses, 

 the number is a reference to the page of that part of the Revue 

 just mentioned. The Revue is not supposed to contain critical 

 remarks on the papers of which it gives an account, but this 

 part contains an exception : a fundamental error is pointed 

 out in A. Kempe's (51) attempt to prove the impossibility of 

 an algebraic solution of the equation of degree higher than the 

 fourth. Critical accounts have been attempted here, however 



