522 Scientific Intelligence. 



work on the subject which has been carried out within the last 

 twenty years. He has made a selection, therefore, of the cases 

 which throw light" upon the general lines along which stereo- 

 chemical research has advanced. The book is a valuable contri- 

 bution to chemical literature, and its references and index are 

 excellent features. t. b. j. 



5. Condensation of Water Vapor in the Presence of Radium 

 Emanation. — Mine. Curie has shown that radium particles have 

 the power of condensing water vapor. A cloud is formed and 

 made visible by an arc light. The formation of the cloud occurs 

 far below the saturation pressure. The phenomenon differs from 

 the effect produced in the condensation of water vapor by ions. 

 The condensation disappears under the effect of an electric field, 

 and disappears after the field is removed. — C. R., cxlv, pp. 1145- 

 1147, 1907. j. t. 



6. Anode Rays. — E. Gehrcke and O. Reichenheim filled the 

 anode with various salts which were raised to a high temperature 

 and formed a family of positive rays, which conveyed particles of 

 the salts to a suitably placed screen. In order to increase the 

 brilliancy of the effects it was necessary to mix the salts with 

 some inert substance, pulverized graphite, for instance. The 

 color of the fluorescence produced was always identical with that 

 of the canal rays. The anode rays emerge perpendicularly to 

 the surface of the anode. They were directed by a magnetic 

 field in a direction opposite to that taken by the negative rays. 

 They also showed the Doppler effect. Proceeding to calculation, 

 they obtained the value of v = 1 ^-lO'cm/sec for the fastest rays 

 and v = l'10 7 cm sec for the rays of mean velocity. From the 



anode fall of potential the value — '= 0-45 - 10 3 was obtained for 



n\ 



sodium vapor; comparing this with the value — = ^"lO 3 for 



hydrogen, the authors obtain 21 for the atomic weight of sodium. 

 In a similar manner atomic weights of other substances were ob- 

 tained. — Ann. der Physik, Xo. 5, 1908, pp. 861-884. J. T. 



7. Handbuch der Spectroscopic / by H. Kayser. Vol. IV, 

 pp. xix + 1248. Leipzig, 1908 (S. Hirzel). — In order to place the 

 fourth volume of Kayser's treatise in proper perspective it seems 

 desirable to call attention both to the author's original plan and 

 to the chief characteristics of the preceding volumes. As stated 

 in the preface to the first volume (which appeared in 1900*), it 

 was Kayser's intention to fill a very important gap in the litera- 

 ture of spectroscopy by writing and compiling a reference book 

 which should possess the greatest possible completeness and also 

 present a critical recapitulation of the views and opinions held 

 with regard to disputed questions. 



Conformably to this plan the first volume dealt with the his- 

 tory of the subject and also contained a detailed description of all 



* See this Journal, vol. x (1900), p. 464 ; xiv (1902), p. 460 ; and xx (1905), 

 p. 69. 



