Chemistry and Physics. 541 



3. Allerts Commercial Organic Analysis; edited by W. A. 

 Davis and Samuel S. Sadtler. Volume VII. 8vo, pp. 563. 

 Philadelphia, 1913 (P. Blakiston's Son & Co. Price $5.00).— 

 The present volume of the entirely re-written fourth edition of 

 this important work deals with the vegetable alkaloids (continued), 

 glucosides, non-glucosidal bitter principles, animal bases includ- 

 ing ptomaines, animal acids, lactic acid, cyanogen and its deriva- 

 tives. The contributors, of whom four belong in England and 

 three in the United States, appear to have maintained the high 

 standard of excellence of the preceding volumes. n. l. w. 



4. A Foundation Course in Chemistry for Students of Agri- 

 culture and Technology ; by J. W. Dodgson and J. A. Murray. 

 12mo, pp. 244. London, 1913 (Longmans, Green & Co. Price 

 Si. 10). — This small textbook presents a short course in elementary 

 chemistry in which the simpler fundamental principles and the 

 more important facts appear to be very well presented. About 

 75 pages are devoted to organic compounds. There is appended 

 to the book a rather extensive list of well-chosen questions, 

 including a few good examples for calculation. h. l. w. 



5. Osmotic Pressure : by Alexander Findlay. 8vo, pp. 84. 

 London, 1913 (Longmans, Green & Co. Price $1.00 net). — This 

 is one of a series of monographs on inorganic and physical chem- 

 istry, edited by the author of the one under consideration, which 

 are designed to place before advanced students of chemistry 

 certain sections of the subject in a comprehensive manner, with 

 particular attention to recent investigations. The present volume 

 treats its subject in a very able manner, and it is to be recom- 

 mended to those who are interested in this important field of 

 investigation. h. l. w. 



6. The Possibility of Moleadar Agitation at the Absolute 

 Zero. — Two formulae have been given b} 7 Planck for the energy 

 of a resonator. The second formula differs from the first by the 



addition of the term — — . If the curves representing these two 



expressions are plotted on the same diagram with energy (ordi- 

 nates) as a function of the absolute temperature (abscissae) it 

 becomes clear that the first curve starts at the origin and always 

 remains below the straight line E = k T. This is consistent with 

 the classical theory. On the other hand, the second curve begins 



with the ordinate at the absolute zero, and becomes asymp- 

 totic to the above-mentioned straight line when the temperature, 

 T, approaches infinity. Thus the resonator would have an amount 



of energy given by at the absolute zero. This result is in 



contradiction to the classical theory. The differential coefficient 

 of the energy with respect to the temperature, that is, the spe- 

 cific heat, is the same for both of Planck's formulae. 



Starting with these considerations, A. Einstein and O. Stern 

 have been able to compare certain theoretical loci with the curve 



