782 



SCIENCE. 



[N. S. Vol. VII. No. 179. 



the reader to supplement the necessarily brief 

 discussion of such topics. The apparatus for 

 experimental work is well selected, and gives 

 opportunity for typical demonstrations on al- 

 most every problem, with a minimum of cost, 

 while many additional exercises are given, for 

 which no special apparatus is needed. 



H. C. Waeken. 



SCIENTIFIC JOURNALS. 

 Journal of Physical Chemistry, May. ' The 

 Transference Number of Hydrogen :' by Doug- 

 las Mcintosh. An attempt to determine the 

 transference number for hydrogen in different 

 circles by the Helmholtz method, using gas 

 electrodes, but it was found that the method is 

 not applicable to gas cells, probably owing to 

 the solubility of the electrode in the electrolytic 

 solution. ' Single Differences of Potential :' by 

 Hector R. Carvelh. The conclusion is drawn 

 that the values given by drop electrodes does 

 not give true single differences of potential. 

 ' Acetonechloroform :' by Frank K. Cameron 

 and H. A. Holly. A study of the camphor- 

 like substance discovered by Willgerodt formed 

 by adding potassium hydroxid to a mixture of 

 acetone and chloroform. From the formula of 

 the substance it would appear to be a simple ad- 

 dition-product, but this is shown not to be the 

 case, and it cannot be resolved into its con- 

 stituents by direct means. While the substance 

 contains water, it is present not as a hydrate, 

 but apparently in a solid solution. Notes on 

 new books, including an excellent review of the 

 last edition of Mendeleef's Principles of Chem- 

 istry ; Journal Reviews. 



The Astrophysical Journal for May, com- 

 pleting the seventh volume, opens with an 

 article by Professor J. Wilsing, of the Potsdam 

 Astrophysical Observatory, which argues that 

 the results obtained by Messrs. Humphreys and 

 Mohler on the influence of pressure on the 

 wave-length of lines in the spectra of the metals 

 can be explained as an effect of damping of 

 the vibrations to which the emission of light is 

 due. Mr. R. H. Tucker, of the Lick Observa- 

 tory, follows with an article on ' The Corre- 

 spondence of the Photographic Durchmusterung 

 with the Visual.' Mr. C. W. Crockett, of the 



Rensselaer Polytechnic Institute, reviews in two 

 articles the caustic of the right parabolic cylin- 

 der and the parabolic mirror. Mr. Frank Mc- 

 Clean contributes a paper read before the 

 Royal Society on a comparison of oxygen with 

 the extra lines in the spectra of the helium 

 stars, as also a summary of the spectra of 

 southern stars, and Professor H. A. Rowland 

 and Mr. C. N. Harrison contribute the final 

 article on ' Arc Spectra of Zirconium and Lan- 

 thanum.' 



The sixteenth volume of the Educational Ee- 

 vieiv commenced with the June number, which 

 includes the following articles: ' Harris' Psycho- 

 logic Foundations of Education,' by John 

 Dewey : ' Scope and Function of Secondary 

 Education,' by Nicholas Murray Butler; 'Teach- 

 ing European History in College,' by James H. 

 Robinson ; Religious Periods of Child-growth,' 

 by Oscar Chrisman ; ' Better Training for Law 

 and Medicine,' by Charles F. Thwing ; The 

 'Key to Rousseau's Emile,' by Samuel Weir, 

 and ' Attitude of Massachusetts School Author- 

 ties toward a Science of Education,' by John 

 G. Thompson. 



SOCIETIES AND ACADEMIES. 



THE CHEMICAL SOCIETY OF WASHINGTON. 



The regular meeting was held on April 14th. 



The first paper of the evening was read by 

 Dr. Hillebrand and was entitled ' The Volu- 

 metric Estimation of Vanadium in the Presence 

 of small Amounts of Chromium, with especial 

 Reference to the Analysis of Rocks and Ores.' 

 When chromium has been estimated colorimet- 

 rically, as detailed in a previous paper, the 

 vanadium can, in many instances, be estimated 

 without separation from the chromium by the 

 well-known method of titration with KMnO^. 

 With considerable chromium present the error is 

 increased by the difficulty of getting sharp end 

 reaction, due to the color of the chromic salt 

 and to the oxidizability of CtiOs in hot solutions, 

 but the author shows how to ascertain and 

 apply a proper correction within certain limits. 



The method is especially applicable to rocks, 

 iron ores, clays, coals, etc. , in which chromium 

 is seldom an important constituent quantita- 

 tively. 



