NA TURE 



361 



THURSDAY, SEPTEMBER 23, 1909. 



PHILOSOPHY AND HISTORY OF SCIENCE. 

 (i) Das Prinzip der Erhaltimg der Energie. By Dr. 

 . Max Planck. Zweite Auflage. Pp. xvi + 27S. 

 . (Leipzig : B. G. Teubner, 1908.) Price 6 marks. 



(2) I'ercrbung, Gcdaclitnis tind Transzcndcntale Erin- 

 nerungen vom Standpunktc des Physikers. By Dr. 

 Gustav Eichliorn. Pp. x+116. (Stuttgart: Julius 

 Hoffmann, 1909.) Price 2.50 marks. 



(3) Dc la Methodc dans les Sciences. By Profs. H. 

 Bouasse, &c. Pp. 412. (Paris: F6Iix .Alcan, 1909.) 



(4) Materialistische Epochc und monistische Bewe- 

 gung. By Paul Volkmann. Pp. 30. (Leipzig : 



. B. G. Teubner, 1909.) Price i mark. 



(5; Das Theorem dcs Pythagoras. By Dr. H. .\. 



Naber. Pp. xii + 240. (Haarlem: P. Visser, 1908.) 



Price ys. 



(6) Essai sur la notion de Theorie physique da Platon 

 a Galilie. By Pierre Duhem. Pp. 144. (Paris : 

 A. Hermann and Son, 1908.) Price 5 francs. 



(7) 11 passato ed il presente delle principali Teorie 

 gcometriche. Terza editione. By Prof. Gino Loria. 

 Pp. xxiv4-476. (Torino: Carlo Clausen, Hans 

 Rinck Succ, 1907.) 



(l) TN 1887 the Gottingen Faculty of Pliilosophy 

 -L offered a prize for the best essay, historical 

 and critical, on the physical concept of energy, and 

 the principle of conservation of energy. The prize 

 was awarded to Dr. Max Planck, and his essay now, 

 in its second edition, finds a fitting place in the 

 series which the Teubner Press are issuing bearing 

 the title of the first volume by Poincare, " Science 

 and Hypothesis." 



The volume is divided into three sections. The 

 first is historical ; the second deals with statements 

 and proofs of the principle ; while the third discusses 

 the various forms of energy and their symbolic re- 

 presentations. 



" The Principle of Conservation of Energy " is a 

 somewhat elastic title for a thesis. Had Prof. Planck 

 included every application of the principle or every 

 investigation in which the principle plays an Important 

 part, his work would have swelled out into a treatise 

 containing pretty well the whole of physics and a 

 large part of chemistry. The author has been wise 

 in restricting his inquiries to a narrow field. He ex- 

 cludes all reference to the less easilv understood second 

 law or principle of degradation of energy. That prin- 

 ciple is far more difficult to understand than the first 

 law, and it is doubtful whether at the time of writing 

 the essay Prof. Planck could have been in a position 

 to give a satisfying account of it. It teaches us that 

 a community of molecules tends towards a state of 

 socialism in which wealth in the form of energy is 

 evenly distributed among the molecules, but that as 

 the change takes place, this energy becomes less and 

 less available for useful purposes, until the system 

 comes to a deadlock, when all progress and activity 

 ceases, and no further work is done by the system. 

 The first law, which tells us that wealth in the form 

 of energy cannot be created or destroyed, so that one 

 molecule cannot grow richer without making another 

 NO. 2082, VOL. 81] 



poorer, is much easier of comprehension, and gave 

 Prof. Planck abundant material for discussion. 



While the treatment can scarcely be described as 

 exhaustive, this impression may be to a large extent 

 attributed to the changes which have taken place in 

 our knowledge of physical phenomena since the thesis 

 was written. It would have been next to impossible 

 for the author to have brought the book up to date 

 by the inclusion of this later work; and, after all, 

 what has happened in the interval? Have we not, 

 as a general rule, taken the principle of conservation 

 of energy for granted, and merely investigated fresh 

 applications of it? Even in connection with the 

 phenomena of radio-activity, no one has cast any very 

 serious doubts on the validity of the principle. For 

 critical writings on the subject, we must go back to 

 the time of Clausius, Mayer, Joule, and the earlier 

 works of Helmholtz and Lord Kelvin ; and these are 

 discussed in the first section. An attempt to draw in 

 recent applications might have confused the issue 

 rather than otherwise. 



(2) While many attempts have been made to formu- 

 late a physical basis for the phenomena of life — for 

 example, by Loeb in Germany and Dr. F. J. Allen in 

 this country — considerable difficulty is experienced in 

 explaining thought, memory, and the hereditary trans- 

 mission of characters, none of which concepts 

 appears easily reconcilable with the ordinary properties 

 of matter, at any rate in its inert state. Dr. Gustav 

 Eichhorn would now maintain that electric theories 

 of matter open up new possibilities. For the discovery 

 of electrons, the theory that matter is a complicated 

 aggregate of electrons, and the existence of mutual 

 relations between matter and aether, are fully consistent 

 with the view that the phenomena of thought and 

 heiedity are caused by particular states of the EEther 

 associated with the molecules of the material organism. 

 Part of the book, dealing with hallucinations and 

 " transcendental memories," was written ten years 

 ago. The author does not profess to give an e.x- 

 haustive or complete study of the problems with 

 which the book deals, and in view of the fact that the 

 electron theory is comparatively recent, his claims to 

 have treated the subject from a new standpoint are not 

 without foundation; but isn't all this the old notion of 

 spiritualism and " animal magnetism " merely served 

 up under a different name? If not, the resemblance is 

 very striking, and the difference not very obvious. 



(3^ The collection of articles edited by Dr. Thomas 

 under the designation of " Method in the Sciences " 

 owes its publication to the growing importance at- 

 tached to philosophy of science, and in particular to 

 methodology in French educational curricula follow- 

 ing Auguste Comte. It is pointed out that both text- 

 books and original articles leave a gap in such litera- 

 ture of the subject as is available for students, and 

 this gap it has been the object of the present volume 

 to assist in filling. In reviewing this book, one is 

 tempted to enlarge on the fact that an educational 

 system which tries to mould all teachers or students 

 according to a common pattern can never be efficient. 

 No better preventive against this deadly uniformity can 

 be suggested than the publication of a book represent- 

 ing the combined experience of all sorts and con- 



O 



