314 Scientific Intelligence. 



hypothesis that the magnetometer deflections noted in the preced- 

 ing case (coil perpendicular to magnet's field) might have been 

 due to some magnetic property of the wire or bobbin which 

 existed only at very low temperatures. The very small deflec- 

 tions obtained could be fully accounted for as arising from slight 

 asymmetry in the coil, hence the hypothesis just mentioned is 

 untenable. " Other experiments finally disposed of all idea of 

 direct magnetic action, and the actual presence of a continuing 

 current was proved independently by attaching galvanometer 

 leads to the points on the coil, and suddenly cutting the wire 

 between them under the helium, when a swing of the galvanom- 

 eter needle was observed, while the magnetometer immediately 

 went to zero." It is thus seen that currents analogous to the 

 molecular currents imagined by Ampere have been realized experi- 

 mentally. — Nature, xciii, p. 481, July 9, 1914. h. s. u. 



6. The Elements of Electricity and Magnetism ; by Wm. S. 

 Franklin and Barry Macnutt. Pp. viii, 351, with about 260 

 figures. New York, 1913 (The Macmillan Co.). — "The element- 

 ary theory of electricity and magnetism is essentially an extension 

 of the science of mechanics, and the purpose of this book is to 

 develop the science of electricity and magnetism from this point 

 of view." Since the sequence of subjects differs from that fol- 

 lowed in many other text-books of the same grade it may not be 

 superfluous to enumerate the titles of the chapters, which are : 

 " I The Electric Current. Its Chemical Effect. II Resistance 

 and Electromotive Force. Ill The Magnetism of Iron. IV 

 Magnetic Effect of the Electric Current. V Induced Electro- 

 motive Force. VI Electric Momentum. Inductance. VII Elec- 

 tric Charge. The Condenser. VIII Phenomena of Electrostatics. 

 IX Electric Oscillations and Electric Waves, and X Electrical 

 Measurements." 



The material selected seems to be presented in a manner pre- 

 eminently adapted to attract and hold the attention of the stu- 

 dent. Some of the features which combine to produce this 

 impression may be briefly summarized as follows. The diagrams 

 are large, clean-cut, and practical. Important facts, principles, 

 and theorems are emphasized by italics. Mechanical analogies 

 are stated and formulated in columns parallel to the correspond- 

 ing electrical relations. 158 wholesome problems (with answers) 

 are distributed through the volume. The appendices deal with 

 terrestrial magnetism, ship's magnetism, and the compensation of 

 the compass, miscellaneous phenomena (thermo-electricity, Zee- 

 man effect, etc.), and miscellaneous practical applications (quadru- 

 plex and wireless telegraphy, etc.). Unfortunately the present 

 volume does not differ in the minutest detail (save the date) from 

 the edition published in July, 1908, and hence all of the typo- 

 graphical and other errors have been retained. h. s. it. 



V. Molecular Physics ; by James Arnold Crowther. Pp. 

 viii, 16V, with 29 figures. Philadelphia, 1914 (P. Blakiston's Son 

 and Co.). — A fair idea of the nature and scope of the text may be 



