192 



SCIENCE. 



[N. S. Vol. II. No. 33. 



given relating to water works. These 

 omissions show the defects of the author's 

 system of classification, and demonstrate 

 how impossible it is to write a satisfactory 

 one-volume treatise on civil engineering at 

 the present day. A comprehensive treat- 

 ise, like the Handhueh der Ingenieurwissen- 

 schaften, must consist of many volumes and 

 be the work of many men. 



Mansfield Merbiman. 

 Lehigh University, July 29, 1895. 



Electricity Up to Date for Light, Power and 

 Traction. John B. Verity, London and 

 New York, Frederick Warne «& Co.' 

 1894. 



The preface of this book tells us that 

 15,000 copies have found their way into cir- 

 culation. The title is a misnomer, unless the 

 date is mentioned. In these days of active 

 investigation and rapid application of dis- 

 covered principles a book on electricity is 

 out of date as it drops from the press. This 

 statement is exemplified in this publication. 

 The recent lucid investigations of Mr. R. E. 

 Crompton on electric heating do not appear, 

 and the surprising results of Mrs. Ayrton 

 on the electric arc receive no mention. 

 The various prime movers are mentioned, 

 excepting the steam turbine, which, per- 

 haps, is the most promising of all motors. 

 The author ignores pretty generally what 

 America is doing in the electric field, except 

 in the case of Edison, to whom he gives 

 credit for what was known before Edison 

 was born- — ' the subdivision of the electric 

 light.' 



One of the first and certainly one of the 

 simplest arc lamps, and the one most used, 

 the Brush, I'eceives no mention. There are 

 several expressions which ought to be 

 omitted from popular books, to prevent the 

 spreading of erroneous ideas. Among these 

 are ' Storage of Electricity,' used in this 

 book as the head of a chapter ; ' Electric 

 Pressure,' for ' Difference of Potential.' 



The confounding of these terms causes great 

 confusion in the schools. We expect better 

 things in a book which professes to be both 

 scientific and popular. On page 184 is the 

 statement that in a wire through which a 

 current of electricity is passing ' the heat 

 generated is proportional to the quantity of 

 current used;' it would have been just as 

 easy to have stated the exact law. The 

 bo«k is well printed and illustrated, but it 

 is difiicult to treat so large a subject in 200 

 pages with success. J. W. Mooee. 



Lafayette College. 



Neudrueke von Sehriften und Karten itber Me- 

 teorologie und Erdmagnetismus herausgegeben 

 von Professor Dr. G. Hellmann, No. 4-- E. 

 Halley, W. Whiston, J. C. Wilcke, A. 

 VON Humboldt, C. Hansteen. Die dltesten 

 Karten der Isogonen, Isoklinen, Isodynamen ; 

 1701, 1721, 1768, I8O4., 1825, 1826. Berlin, 

 A. Ascher & Co. 1895. Sieben Karten 

 in Lichtdruck mit einer Einleitung. 26 

 pp., 4to. 



The above forms No. 4 of the very inter- 

 esting series of reprints in facsimile of epoch- 

 making rare old books or charts in Meteor- 

 ology and Terrestrial Magnetism edited by 

 the well-known meteorologist and bibli- 

 ographer. Professor Hellmann, of Berlin. 



Like its predecessors,* the number before 

 us commends itself by its keen, critical and 

 thorough research, by its beautiful typo- 

 graphical execution and by the lowness of 

 the price. Hardlj' one of the seven charts 

 given could be obtained for the price (5 

 marks) asked for the whole. It is needless 

 to remark that the editor of these successful 

 reprints and his cooperators, the German 

 Meteorological ^ Society and its Berlin 

 Branch, have thus merited the warmest 



*No. 1. L. Eeynman: Wetterbiichlein.Von wahrer 

 Erkenntniss des "Wetteis. 1.510. 



No. 2. Blaise Pascal: Rocit de la Grande Experi- 

 ence de I'Equilibre des Liqueurs. Paris, 1648. 



No. 3. Luke Howard: On the modilications of 

 clouds. London, 1803. 



