Chemistry and Physics. 463 



7. Materialien der Stereochemic ; von C. A. Bischoff. 8vo, 

 pp. cxxxvi + 1977. Braunschweig 1904 (Vieweg und Sohn). — 

 The two large volumes under consideration are made up of nine 

 yearly reports on stereochemistry embracing the years 1894-1902. 

 Each year's report is divided into four sections, treating of general 

 stereochemistry, optical isomerism, the geometrical isomerism of 

 optically inactive bodies, and the relations between position in 

 space and chemical reactions. Those who have not followed 

 closely the progress of stereo-chemistry will be surprised that 

 so extensive a work could be written upon the investigations of 

 nine years in this subject, concerning which nothing was heard 

 twenty years ago. Regardless of some defects, such as slight 

 attention to American work, the book will be found indispensable 

 to those who are interested in this line of research. t. b. j. 



8. Die Meter ogenen Gleichgewichte vom StandpunMe der 

 Phasenlehre; von Dr. H. W. Bakhuis Roozeboom. Vol. II, Part 

 I, pp. '467, 8vo (Vieweg und Sohn, 1904). — The first volume of this 

 book has already been reviewed in this Journal [4], xii, 463, 1 901. 

 The present volume is devoted to systems made up of two com- 

 ponents in which, as solid phases only the components occur, and 

 excluding the cases where solid compounds or mixed crystals are 

 present. Frequent use is made of diagrams and figures in three 

 dimensions. For students of the phase rule this book when 

 finished should take the part that Ostwald's Lehrbuch does for 

 students of physical chemistry in general. it. w. f. 



9. Phosphorescence. — A long paper on this subject is contrib- 

 uted by P. Lenaed and V. Kla.tt, and relates to the phosphores- 

 cence of sulphides of the alkali earths. This phosphorescence 

 is due to those sulphides, to a small trace of certain metals, and to 

 fusible additions. Together with the chemical nature, the physical 

 structure conditions the character of the light. This light 

 appears only at a glow heat, never at a cold or wet stage, and is 

 destroyed by pressure. Care was taken to obtain definitely pure 

 substances. The addition of small trace of metals changes the 

 intensity of the light, and its duration. No displacement of 

 bands in the spectrum was noticed. The authors believe that 

 their study of the peculiarities of the emission bands gives an 

 insight into the complex phenomena of phosphorescence. — Ann. 

 der Physik, No. 12, 1904, pp. 225-282. J. t. 



10. Lippmarts Color Photography. — L. Pfatjndler having at 

 hand a number of Lippman photographs has made a study of 

 " Zenker Streifer" in regard to their bearing on the color of the 

 photographs. These streifer, or bands, are spectra or interference 

 colors produced by the varying thickness of the photographic 

 film. These spectra diffused over the photograph give the colors 

 observed. The Zenker bands show that there are series of color 

 pairs which do not contribute to a correct color mixture but 

 which tend to neutralize to black. The Lippman method is not a 

 full solution of color photography. It is, however, a beautiful 

 and highly interesting physical experiment. — Ann. der Physik, 

 No. 12, 1904, pp. 371-384. J. T. 



