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XXXIII. Notices respecting New Books. 



Coins de Physique. Par H. Boua.sse. Sixth Part : htude des 

 Symetries. Paris: Librairie Ch. Delagrave. 

 r PHE sixth part of this important text-book of Physics follows 

 -■- somewhat unfamiliar lines. Beginning with a geometrical 

 study of kinds of symmetry, including the main facts of crystallo- 

 graphic forms (142 pp.), it proceeds to a detailed study of the 

 physical properties which are linked with them. These include 

 the elastic properties, thermal dilatation, electric and magnetic 

 relations, the Hall phenomenon, piezo- and pyro-electricity, phe- 

 nomena of double refraction, pleochroism, absorption, the pheno- 

 mena of Kerr, the anisotropy of liquids, magnetic rotary polari- 

 zation, and liquid crystals (pp. 143-408). 



The treatment throughout is mathematical, and no use is made 

 of modern conceptions based on electronic theory. The matter dealt 

 with loses in consequence a great deal of the vividness which a more 

 physical treatment would have given it. Though we regret this, 

 yet it must at the same time be asserted that Professor Bouasse 

 is producing a masterly treatise which supplements the less mathe- 

 matical text-books of physics. 



Jlesults of Observations made at the Coast and Geodetic Survey Mag- 

 netic Observatory at Cheltenham, Maryland, 1905 and, 1906. 

 "Washington : Government Printing Office. 1009. 



This gives in 110 quarto pages the results derived during 1905 

 and 190(5 from the inagiietographs at the central magnetic station 

 of the U.S. Coast and Geodetic Survey. The monthly tables give 

 hourly values from the declination, horizontal intensity and vertical 

 intensity curves, with the daily maxima and minima and their times 

 of occurrence, also the mean value and the range for each day. 

 Inequalities are derived from the ten quietest days of each month. 

 A table is given of the beginning, duration, and relative intensity 

 of the principal disturbances, numbering 40 in 1905 and _?9 in 

 1906. Only three storms, commencing respectively on March 1, 

 March 31, and Xovember 14, 1905, reached the highest grade, 

 4, of disturbance. Some of the disturbed curves are reproduced. 

 The Observatory is also provided with Bosch-Omori seismographs 

 recording N-S and E-AV earth movements. A table is given 

 including particulars of 39 earthquakes recorded in 1905 and 43 

 in 1906. 



An Introduction to the Science of Radioactivity. By C. "VV .Raffety. 

 London : Longmans, Green, & Co. 1909. 



This claims to be a concise and popular account of the properties 

 of the radioactive elements. We consider that the author is 

 justified in his claim, and that his book will be found useful to 

 those who do not profess a first-hand acquaintance with the 

 subject. Many readers no doubt will find the treatment too 



