Chemistry and Physics. 69 



molecular mass, and the investigation of Fischer and Tafel on 

 sugars. Portions of the book have been re-written and the 

 whole has been revised so as to bring it up to date. 



8. Electro-chemical Analysis. By Edgar F. Smith, Ph.D. 

 12mo, pp. 116. Philadelphia, 1890. (Blakiston).— Dr. Smith has 

 done the science of analytical chemistry a real service by the 

 preparation of this little book. Thanks largely to his own work 

 in this direction, electrolytic methods of separation are rapidly 

 coming into use in the laboratory and by their accuracy of result 

 and convenience of application are gradually replacing purely 

 chemical methods. The chemical student therefore will be glad 

 to welcome a manual in which the theory and practice of electro- 

 chemical quantitative analysis are so well set forth. 



9. Sugar Analysis. By Ferdinand G. Wiechmann, Ph.D., 

 12mo, pp. viii, 187. New York, 1890. (Wiley).— The author's 

 aim in preparing this book has been to meet the needs not only 

 of the sugar house but also of the technical school. In a con- 

 cise form he has collected together the principles and practice of 

 the art of sugar analysis based on the use of the polariscope. 

 The methods of sampling, the preparation of the material for 

 examination, the optical analysis, with and without inversion, 

 etc., are clearly described. The book closes with nineteen valu- 

 able tables, given to facilitate the necessary calculations. 



10. Practical Inorganic Chemistry. By Ebenezer J. Cox,F.C.S. 

 16mo, pp. 51. London, 1890. (Percival & Co.). — This is a brief 

 elementary class book designed to furnish the necessary notes, 

 reactions and analytical tables required by the beginner in prac- 

 tical inorganic chemistry, in the Science and Art department. 



11. Velocity of Sound at very Low Temperatures. — A base 

 line of 1,279 metres was accurately measured, and the interval 

 determined between the flash of a gun at one end and the appear- 

 ance of the sound wave at the other. The following results were 

 obtained : where t is the temperature, x the number of observa- 

 tions, and v the corresponding velocity : 



£ = —10-9 —25-7 —37'8 —45-6 



x 53- 114- 164- 205* 



v 326-1 317*1 309-7 3056m. 



The velocity diminishes therefore 0*603 meter for 1° C. — Phil. 

 Mag., p. 507, Dec, 1890. 



12. Wavedengths of Electrical Oscillations. — In repeating 

 Hertz's work upon this subject. H. K. Waitz has arrived at the 

 following conclusions. 



(1.) A discharge of an inductive coil of a definite species excites 

 oscillations of different wave-length which may. extend over an 

 interval of many octaves. 



(2.) Among these oscillations there is one of greater intensity, 

 the wave-length of which is determined by the dimensions of the 

 conductors. 



(3.) The electrical oscillations in or upon conductors change 



