Chemistry and Physics. 555 



7. A Text-Booh of Physical Chemistry, Theory and Practice; 

 by Arthur W. Ewell. 8vo, pp. 370. Philadelphia, 1909 (P. 

 Blakiston's Son & Co.). — The author states that the book is 

 intended to serve as a laboratory manual, as a text-book to accom- 

 pany recitations or lectures and as a reference book. Much space 

 is devoted to directions for a course of laboratory experiments, 

 including the ordinary physico-chemical measurements' and many 

 which would not ordinarily be given in a students' course. These 

 directions appear to be very good. The theoretical and descrip- 

 tive part of the book is somewhat shorter and less complete than 

 is perhaps desirable. The author assumes that the student has a 

 knowledge of calculus. h. w. f. 



8. A Text-Book of Physiological Chemistry ; by John H. 

 Long. Second edition, revised. 396 pp., with 42 illustrations. 

 Philadelphia, 1909 (P. Blakiston's Son & Co.). — The second edi- 

 tion of Professor Long's book represents a thorough revision and 

 extension of the earlier one. The book is intended primarily for 

 use with laboratory classes, and is unusually well adapted to its 

 purpose. The directions for the practical work are carefully pre- 

 sented, and serve to illustrate the more detailed discussion of the 

 remainder of the text. This plan has, in the reviewer's opinion, 

 distinct advantages over the arrangement of isolated directions 

 found in the so-called manuals of chemistry. The physiological 

 bearings are never allowed to vanish into the background ; so 

 that the functions of living things are continually being empha- 

 sized from the chemical point of view. The book is particularly 

 adapted to the needs of medical students. l. b. m. 



9. Positive Bays. — W. Wien continues his work of 1908 on 

 this subject and concludes his investigation as follows : 



(1) The positive rays of hydrogen at high vacua are less 

 strongly influenced by magnetic fields than at low vacua. 



(2) The rays which are weakened in a magnetic field are also 

 weakened in respect to heat properties and light emission by a 

 second magnetic field to approximately the same degree as those 

 rays which have not been affected by the first magnetic field. 



(3) The light emission is under otherwise equal conditions 

 much less in high vacua than in low, and this is especially true of 

 hydrogen as well as air. 



(4) The magnetic influence does not depend to a large degree 

 upon the potential difference exciting the tube. 



(5) The canal rays of quicksilver do not convey a traceable 

 positive discharge, and no deflection can be observed in strong 

 magnetic fields by direct observation of the light emission. 



The paper concludes with reflections upon the possibility of 

 combination and recombination of ions and electrons, and on the 

 possibility of light being emitted by positive ions in a neutral 

 condition. — Ann. der Physik, No. 12, 1909, pp. 349-368. j. t. 



10. The apparent Fusion of Carbon in the Singing Arc and 

 in Sparks. — M. La Rosa gives a resume of the work of Despretz 

 and Moissan on the production of artificial diamonds, and con- 



