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XXXVII. Notices respecting New Books. 



An Introduction to the Theory of Optics. By Arthur Schuster, 

 Ph.D., Sc.D., F.R.S., Professor of Physics at the University of 

 Manchester. London : Edward Arnold. 1904. Pp. xv-f 340. 



r PIIiS important work is divided into two parts. In Part I. the 

 J- author deals with the more elementary aspects of the subject, 

 while Part II. is intended as an introduction to the higher 

 branches of it. 



The first two chapters are of an introductory nature, and deal 

 with simple periodic disturbances and their composition, and with 

 the kinematics and kinetics of wave motion. In Chapter III. the 

 author deals with some general principles, optical length and optical 

 distance, Fermat's principle, and the principle of reversibility. 

 Chapter IV. is devoted to interference effects, Chapter V. to dif- 

 fraction, and Chapter VI. to diffraction-gratings. The theory of 

 optical instruments, with special reference to resolving power and 

 brightness, is considered in Chapter VII. In Chapter VIII. we 

 have an account of the propagation of light in crystalline media, 

 while Chapter IX., which is the concluding chapter of Part I., deals 

 with the interference of polarized light. 



In Part II. the author gives a sufficiently complete account of 

 the matters dealt with to place the reader who has mastered this 

 portion of the book in a position to study with profit the writings 

 of the leading authorities on the subject. Chapter X. begins with 

 a general mathematical account of strains and stresses, and then 

 deals with the equations of motion in a disturbed medium, and the 

 electromagnetic theory of light. Dispersion and absorption are 

 next considered in Chapter XI. Chapter XII. contains an account 

 of rotatory effects, including the rotation of the plane of polar- 

 ization, rotatory dispersion, and the Zeeman effect. In Chapter 

 XIII. the author considers the propagation of energy through 

 a medium, and in the concluding Chapter XIV. the nature of 



The work is a contribution to optical literature for which all 

 earnest advanced students of the subject will feel deeply grateful 

 to the author : it combines clearness of expression, comparative 

 simplicity and striking originality of treatment, with a keenuess of 

 critical insight but seldom to be found in works of a similar scope. 



The Electric Furnace. By Hexri Moissan, Membre de VInstitut, 



Professor of Chemistry at the Sorlonne. Translated by A. T. 



de Mouilpied, B.Sc, Ph.D., Assistant Lecturer in Chemistry in 



the L'niversitv of Liverpool. London: Edward Arnold. 1904. 



Pp. xii + 308." 



Chemists and electro-chemists whose knowledge of French is too 



imperfect to enable them to read Professor Moissan's great work 



on the electric furnace in the original will welcome the appearance 



of an English translation of it. The name of Moissan is so well 



Phil. Mag. S. 6. Vol. 9. No. 51. March 1905. 2 C 



