104 Scientific Intelligence. 



attention. The chapters of the third book take up, in order, the 

 distribution of magnetism at the earth's surface, the cause of ter- 

 restrial magnetism, the diurnal variations, and the secular changes. 

 The author's style is pleasing and he presents the entire subject 

 in a clear, logical manner. h. s. u. 



12. Magneto and Electric Ignition; by W. Hibbert. Pp. 

 154, with 79 figures. London and New York, 1912 (Whittaker 

 &> Co.).— This compact little volume gives effectively answers to 

 all the most important questions which arise in connection with 

 the details of construction and maintenance of such internal com- 

 bustion engines as are used in automobiles, motor cycles, aero- 

 planes, etc. It is written in a popular style, and the small 

 amount of electrical theory necessary is made as clear as possible 

 by means of well-selected, familiar analogues. The book should 

 be of great value to non-scientific readers who need practical, 

 concise rules for locating faults in cells, electrical connections, 

 spark-plugs, and other parts of the entire engine system, h. s. u. 



13. General Physics ; by W. Watson. Pp. xiii, 564, with 311 

 figures. New York, 1912 (Longmans, Green and Co.). — This 

 book has been written conformably to the author's opinion that a 

 considerable number of the simpler physical phenomena, which 

 are customarily included in a first course for general and techni- 

 cal college students, can be advantageously omitted, or dealt with 

 very briefly, so as to save time and space for greater thorough- 

 ness in the treatment of the more important problems and of the 

 recent developments of pure and applied physics. Attention is 

 directed to the key-note of each paragraph by titles inset in 

 heavy type at the margin of the text. The index is preceded by 

 a generous list of questions and examples grouped to correspond 

 to the "books" and chapters. The numerical answers are col- 

 lected at the end of this list of exercises. The treatment is logi- 

 cal, the presentation lucid, and the diagrams are clear, but the 

 type seems to be somewhat too small with the spacing compressed. 

 We have noticed only one slip, namely, on page 357, "this phe- 

 nomena." h. s. u. 



14. Gli Elettroni nei Metalli ; by Lavoro Amaduzzi. Pp. 

 147. Bologna, 1912 (Nicola Zanichelli). — This monograph, a 

 companion to the author's previous publication, " Ionization and 

 Electric Convection in Gases," covers the same field in the metals 

 that the previous work did for gases. The conduction of elec- 

 tricity through metals, and other phenomena due to the presence 

 of electrons in metals, are discussed from the theoretical stand- 

 point. Some of the topics discussed are : conductivity; magnet- 

 ism; relations of metals in contact with gases, liquids, and other 

 metals; galvanic and thermo-magnetic phenomena; and the theory 

 of electrons in relation to radiation. h. b. l. 



