482 



SCIENCE. 



[N. S. Vol. XII. No. 300. 



celebration the Cambridge Philosophical So- 

 ciety held a special memorial meeting at which 

 a number of mathematico-physical memoirs 

 were presented. These now appear in print 

 for the first time in the volume whose title- 

 page is quoted above. A note on the page 

 following the title-page states that "These 

 Memoirs are also issued as Volume XVIII. of 

 the Transactions of the Cambridge Philosophical 

 Society." The book contains also the 'Order 

 of Proceedings at the formal celebration by the 

 University of Cambridge of the Jubilee of Sir 

 George Gabriel Stokes, Bart., Lucasian Pro- 

 fessor, 1849-1899'; and 'The Eede Lecture: 

 La thiorie des ondes lumineuses : son influence 

 sur la physique moderne,' delivered by Profes- 

 sor Alfred Cornu on June 1, 1899. An excel- 

 lent portrait of Sir George appears as a fron- 

 tispiece, and the volume is supplemented by 

 twenty-five plates illustrating the diflferent 

 memoirs and by an index. 



The semi-popular lecture by Professor Cornu, 

 in addition to giving an admirable summary of 

 the century's progress in physical optics, pre- 

 sents the conclusions of a special study of the 

 work of Newton in this field. To the general 

 reader as well as to the specialist this eloquent 

 address cannot fail to prove interesting and 

 instructive ; and the scientific world must ap- 

 plaud the sentiment expressed in the author's 

 closing words : 



' 'Que 1' University de Cambridge soit fiSre de sa 

 chaire Lucasienne de Physique mathematique, 

 car, depuis Sir Isaac Newton jusqu'a Sir George 

 Stokes, elle contribue pour une part glorieuse 

 aux progres de la Philosophic naturelle." 



The memoirs proper of the volume are 

 twenty-two in number and by as many diflTer- 

 ent authors. They appertain to a wide variety 

 of subjects and are in general strictly technical 

 in character. They are appropriately not too 

 prolix, however ; the briefest occupying'only 3 

 and the longest only 56 pages. Pure and ap- 

 plied mathematics are about equally repre- 

 sented, though some of the papers are a little 

 difficult to classify. The titles and authors of 

 the memoirs are as follows : 



I. ' On the analytical representation of a uni- 

 form branch of a monogenic function,' by G. 

 Mittag-Leffler. 



II. ' Application of the partition analysis to 

 the study of the properties of any system of con- 

 secutive integers,' by Major P. A. MacMahon. 



III. ' On the integrals of systems of differen- 

 tial equations,' by A. E. Forsyth. 



IV. ' Ueber die Bedeutung der Constante b 

 des van der Waals'schen Gesetzes,' von L. 

 Boltzmann und Dr. Mache, in Wien. 



V. ' On the solution of a pair of simultaneous 

 differential equations which occur in the lunar 

 theory,' by Ernest W. Brown. 



VI. ' The periodogram of magnetic declina- 

 tion as obtained from the records of the Green- 

 wich Observatory during the years 1871-1895 

 (Plates I. II.),' by Arthur Schuster. 



VII. ' Experiments on the oscillatory dis- 

 charge of an air condenser, with a determina- 

 tion of '«;',' by Oliver J. Lodge and R. T. Glaze- 

 brook. 



VIII. ' The geometry of Kepler and Newton,' 

 by Dr. C. Taylor. 



IX. ' Sur les groupes continus,' par H. Poin- 

 car6. 



X. ' Contact transformations and optics,' by 

 E. O. Lovett. 



XI. ' On a class of groups of finite order,' by 

 W. Burnside. 



XII. ' On Green's function for a circular disc, 

 with applications to electrostatic problems,' by 

 E. W. Hobson. 



XIII. ' Demonstration of Green's formula for 

 electric density near the vertex of a right cone,' 

 by H. M. Macdonald. 



XIV. ' On the effects of dilution, temperature 

 and other circumstances on the absorption spec- 

 tra of solution of dydimium and erbium salts ' 

 (Plates III. -XXIII.), by G. D. Liveing. 



XV. ' The Echelon Spectroscope,' by A. A. 

 Michelson. 



XVI. ' On minimal surfaces,' by H. W. Rich- 

 mond. 



XVII. ' On quartic surfaces which admit of 

 integrals of the first kind of total differentials, ' 

 by Arthur Berry. 



XVIII. 'An electromagnetic illustration of 

 the theory of selective absorption of light by a 

 gas,' by Horace Lamb. 



XIX. ' The propagation of waves of elastic 

 displacement along a helical wire,' by A. E. 

 H. Love. 



