June io, 1922J 



NA TURE 



739 



^(.ometry, the better. The gradient is too steep in the 

 trigonometrical portion. 



(9) Why does Mr. Sandon use the title " Mathe- 

 matical Tables " } In reality the booklet seems to 

 be intended as a pocket cyclopaedia of much, if not 

 I all, knowledge. In 96 small pages we get treatises 

 nn arithmetic, algebra, mechanics, calculus — gam.ma 

 mctions are also included — astronomy, insurance, 

 (ology, philology, chemistry, earthquakes, the Morse 

 )de, the size of wall-paper, ship watches and bells, 

 and Suffolk and Essex measures of butter and cheese, 

 to name only a selection. The book may be useful, 

 but the mathematical portions are hopelessly marred 

 by misprints. S. Brodetsky. 



I 



Miscellanea Physica. 



La Loi de Newton est la Loi Unique : theorie 

 mecanique de VUnivers. Par Max Franck. Pp. 

 iv+158. (Paris: Gauthier-Villars et Cie, 1921.) 

 12 fr. 50. 



(2) Fluoreszenz tmd Phosphoreszenz im Lichte der 

 neueren Atomtheorie. Von P. Pringsheim. Pp. 

 viii + 202. (Berlin: J. Springer, 1921.) England, 

 144 marks ; Germany, 48 marks. 



(3) La Physique theorique nouvelle. Par Dr. J. 

 Pacotte. Pp. viii + 182. (Paris: Gauthier-Villars 

 et Cie, 1 92 1.) 12 fr. net. 



(4) Mecanismes communs aux phenomenes disparates. 

 Par Prof. M. Petrovitch. (Nouvelle Collection 

 Scientifique.) Pp. v + 279. (Paris: Felix Alcan, 

 192 1.) 8 fr. net. 



(5) tjber Aiher und U rather. Von P. Lenard. Pp. 

 56. (Leipzig : S. Hirzel, 192 1.) 9 marks. 



(6) Physikalische Rundblicke. Gesammelte Reden und 

 Aufsdtze. Von Max Planck. Pp. iv + 168. (Leipzig : 

 S. Hirzel, 1922.) 60 marks. 



(7) Physique elementaire et theories modernes. Par 

 J. Villey. Premiere Partie, Molecules et Atomes : 

 £tats d'equilibre et mouvements de la mati^re 

 (Mecanique, Statique des fiuides, Chaleur, Elasticite 

 et Acoustique). Pp. x-i-197. (Paris: Gauthier- 

 Villars et Cie, 1 92 1.) 15 fr. 



(i) 'np'HE following are the first and the last 

 J. statements in M. Franck's " loi unique." 

 " Tout volume est composee d'une somme de positif 

 qui est son potentiel et de negatif qui est sa masse. , . . 

 Ces variations de potentiel dans Tether sont elles- 

 memes determines directement ou indirectement par 

 I'Esprit." This law " nous supposons capable de tout 

 expliquer " — everything, from the origin of the universe, 

 through Boyle's law, to the constitution of electricity. 

 Such books are the despair of the reviewer. If they 

 are frankly denounced as nonsense, a cry is raised 

 NO. 2745, VOL. 109] 



about an obscurantist hierarchy impervious to all new 

 ideas ; while a careful analysis of them with a view 

 of discovering whether anything valuable is concealed 

 in the tangled mass of verbiage requires an enormous 

 expenditure of time and labour. We announce there- 

 fore that we have not read M. Franck's book, and do 

 not intend to read any book which aims at subverting 

 the foundations of physics unless the author tells us, in 

 terms of its language and concepts, exactly in what 

 respect he finds its conclusions unsatisfactory. 



(2) At the other extreme in this miscellany is Dr. 

 Pringsheim's monograph. It is a summary of all 

 important work on phosphorescence and fluorescence 

 between 1908 (the date of the summary in Kayser's 

 Spectroscopy) and March 1921, the experiments being 

 interpreted so far as possible according to Lenard's 

 theory modified and expanded in accordance with 

 that of Bohr. The author's name is a sufficient 

 guarantee of excellence, and it is unnecessary to say 

 more than that the work is worthy of his reputation 

 and of the traditions of German book -production. 

 The book has a special and melancholy interest in 

 that it is the product of the author's internment for 

 five years in Australia, whither he had gone to attend 

 the British Association meeting as a guest of the 

 Australian Government. He is naturally bitter about 

 his treatment, and every one must agree that the 

 incident was exceptionally unfortunate ; but alas ! 

 war is a succession of unfortunate incidents. 



(3) Intermediate between these extremes is M, 

 Pacotte's volume, which is " un essai historique, 

 critique et methodologique " on the new physics. 

 M. Borel in his preface suggests that nobody has the 

 right to criticise an attempt to compress so much 

 matter within 200 pages who is not prepared to per- 

 form the task better himself ; and we accept his 

 suggestion in so far as we shall make no attempt to 

 discuss whether, in his capacity as historian, M. 

 Pacotte has always traced the true line of develop- 

 ment. But criticism and " methodology " imply a 

 point of view, and it is open to any one to suggest that 

 the point of view is mistaken, without falling under 

 M. Borel's ban ; for if the point of view is wrong the 

 book is not worth writing. We have no intention of 

 declaring categorically that it is wrong, for science 

 may be viewed from many standpoints, all of which 

 are equally legitimate. But we think it right to 

 indicate that M. Pacotte's standpoint is not that of 

 the average physicist, nor yet that of the average 

 philosopher ; both of them will experience some difficulty 

 in understanding what exactly is the task that M. Pacotte 

 is trying to perform. His standpoint is perhaps more 

 nearly that of the mathematician ; but if the book 

 is addressed to mathematicians it is surely a defect 



