NOVEMBEH 23, 1906.] 



SCIENCE. 



653 



Extensive foot-notes point the reader to 

 further sources of information and a full 

 index adds to the value of the book as a work 

 of reference. 



This book can well be declared the most 

 complete and most authentic work extant on 

 this important subject and it should be read 

 by the student of physics to whom a knowl- 

 edge of units and standards is most necessary, 

 as well as by all who wish to be well informed 

 in regard to this interesting topic. 



A thorough test has proved that every recog- 

 nized authority has been consulted and more 

 than one forgotten pioneer in metrology has 

 been given due credit for his contribution to 

 the science. On the whole the book can be 

 commended without reservation and the au- 

 thors are entitled to our best thanks for 

 placing in compact readable form facts that 

 are accessible to the few and obtained by them 

 after long and tedious research. 



J. H. Gore. 



Notes on Electrochemistry. By F. G. Wiech- 

 MANN, Ph.D. 5x9 in., pp. vi + 144. Price, 

 $2.00. New York, McGraw Publishing 

 Company. 1906. 



The aim of the author, as expressed in the 

 preface, has been to give ' a clear and concise 

 presentation of the general principles which 

 underlie electrochemical science,' ' to ofier a 

 general survey of the subject, to serve as an 

 introduction to its study and to aid in the 

 securing of a proper understanding and ap- 

 preciation of the work along individual lines.' 

 In pursuing this aim, the author has de- 

 voted seven pages to general principles of 

 science, fourteen to general principles of elec- 

 trical energy, nineteen to electrochemistry 

 proper, fifteen to electrolytic dissociation, 

 seventeen to electrochemical analysis, forty- 

 six to eleetrotechnology, and ended up with a 

 name and subject index. Each chapter is 

 prefaced by a list of the most important litera- 

 ture on its particular subject. 



We differ in opinion from the author con- 

 cerning the classification of electrotechnical 

 processes; his division into direct-action and 

 indirect-action processes seems to us to be 

 illogically worked out, at least as far as re- 



gards placing ' electrodeposition from fused 

 electrolytes ' among the ' indirect action ' 

 processes. On page 125, line 6, the accidental 

 omission of ' not ' makes the sentence express 

 the reverse of the facts concerning the first 

 news of the manufacture of calcium carbide. 

 There are a few other shortcomings really not 

 worthy of mention, in view of the high stand- 

 ard of excellence and accuracy prevalent in 

 the book. 



The plan of the work is admirable, it is 

 carried out in a masterly manner, and the 

 author has produced an introduction to electro- 

 chemistry which most satisfactorily fulfills his 

 objects, as quoted above. The style is clear 

 and crisp, the information of a high stand- 

 ard of reliability and surprisingly up-to-date. 

 The balance is excellent. For student, tech- 

 nologist, general scientist or man of affairs, 

 it can be highly commended as a trustworthy, 

 satisfactory and inspiring guide into electro- 

 chemistry. 



Joseph W. Eichards. 



SCIENTIFIC JOURNALS AND ARTICLES. 



The Journal of Experimental Zoology, Vol. 

 III., No. 3 (September 1906), contains the 

 following articles : ' Locomotion of Amcebse 

 and Allied Forms,' by Oris P. Dellinger. 



Amoebae and Difflugias are studied from 

 side view as they creep along the polished 

 edge of a glass slide. From such a view the 

 points of attachment and support which fur- 

 nish the key to their locomotion are easily 

 seen. All forms studied alternate the points 

 of attachment and pull and squeeze them- 

 selves along. ' Light Eeactions in Lower Or- 

 ganisms. I. Stentor Coeruleus/ by S. O. 

 Mast. ' The Influence of Light and Heat 

 on the Movement of the Melanophore Pig- 

 ment, especially in Lizards,' by G. H. Parker. 

 A study of the color changes in the skin of 

 the homed toad shows that the so-called re- 

 versed color changes of certain lizards, Stellio, 

 Uromastix, etc., are probably temperature re- 

 actions and not light reactions, and leads to 

 the conclusion that in all melanophores and 

 other like pigment cells, whether they are in 

 the skin or the eyes of the vertebrates or 



