Chemistry and Physios. 73 



is designed to present the most important steps of progress in the 

 various departments of chemistry for the past year. It differs 

 from other publications of the kind, particularly the invaluable 

 and long honored Jahresbericht der Chemie, in that it does not 

 attempt an exhaustive treatment of the subject, but does give a 

 well-selected digest, brief enough to be issued very promptly. 

 This fiVst volume was actually put on sale but a few months after 

 the close of the year whose record it gives; this is a remarkable 

 achievement and if this promptness can be maintained it will 

 ensure the success of the work. The volume is divided into 

 fourteen chapters written by nearly as many well-known authors 

 most of whose names appear on the title page as regular co- 

 editors. The following are subjects of some of the chapters : 

 Physical Chemistry by W. Nernst, also Inorganic by G. Kriiss, 

 Organic by C. A. Bischoff, Physiological by F. Rohmann, etc. ; 

 on Metallurgy by E..F. Diirre, Technology of Carbohydrates and 

 Fermentation processes by M. Marcker and L. Biihring, and of 

 Fats by R. Bendedikt ; Photography by J. M. Eder and E. 

 Valenta. The book is handsomely printed and well bound in 

 cloth. 



6. Chemical calculations with explanatory notes, iiroblems and 

 answers. Specially adapted for use in Colleges and Science 

 Schools, by It. Lloyd Whitklet ; with a preface by F. Clowes. 

 100 pp. London and New York, 1892 (Longmans, Green & Co.) 

 — This is a useful collection of well selected problems under the 

 different departments of chemistry, accompanied by full explana- 

 tions of the methods involved and the solution of typical cases ; 

 the answers to the problems are given in a supplementary chapter. 



7. Contributions to the knowledge of' the discharge of the 

 Ruhmhorff coil ; by Tom Moll; translated from the Beiblatter 

 zu den Annalen der Physik und Chemie, xv, No. 2, 1891. — From 

 the older investigations on the nature and duration of induction 

 currents the author gives a description of the methods and results 

 of Nyland, Rood, Cazin, Mayer and Holtz. He himself employed 

 a photographic method; an image of the spark was thrown by a 

 small concave mirror on a rapidly revolving circular disc which 

 carried a sheet of sensitive paper. The time of closing the pri- 

 mary current and the velocity of rotation of the disc were regis- 

 tered on a revolving cylinder, which also received the trace of a 

 vibrating tuning-fork. A large induction coil was used, its length 

 being 5V cm , its diameter 21 cm ; the strength of the primary cur- 

 rent was measured with a tangent compass. As a general thing 

 the electrodes furnishing the spark were connected with a Leyden 

 jar having an interior coating of about 772 square centimeters. 

 The external resistance in the secondary circuit was always the 

 same and quite small. 



By a study of the photographs thus produced the author ascer- 

 tained the entire duration of the discharge, the intervals of time 

 between the partial discharges and their mean, and this work was 

 performed for sparks of various lengths, for primary currents of 



