Potentiometric Titratioas. I. M. KoLTaoPa -od N. H. m m x . John Wiley 8. Sons. New ~ o r k City. 1926. xii + 345 pp. 14.5 X 23 em. a .50.

-potentiomctrie Titration." is a work that every will welcome. The field that it covers has been the subject of many iecent and valuable papers. Potentiometrie analysir i3 a rather new tool of the greatest practical value to both the re-ch worker and routine analyst. Some systematic and critical collection and evalu- ation of the means and method* so far proposed was orgently needed. Drs. Kolthoffand Furman have done this in a splendid manner. In the very beginning a distinction is drawn

between eondvctametrie and potentiometrie titrations, the former being based on the measure- ment of changing resistance and the latter on hanging r m. f. Both have heretofore been clanzed as electrometrie titrations This dis- tinction seems wise.

The book is well-orpanired. The first part is devoted to s careful rnathematiealanalyri.of the

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Recent Books

theoretical principles involved. Here we find a thorongh discusion of the solubility product rela- tion, of the neutralization of acid-strong, weak, and in mixture-f oxidation-reduction eqlli-

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libria and poteotials, of the general conditions for potentiometrie titratians, ete. Sufficient eases are considered to mahle the chemist to work out the equations for any special system that he may wish to consider. The di9eussion applies to or- dinary titrations also.

The second part in devoted to practical ap- plication*. The various potentiometer systems and methods are deruibed and discused in a very thorough manner. Following this there in a di.eussion, with very full reference., of the silver, mercury, copper. iodine, hydrogen, oxygen and air, higher oxide. quinhydrrme, metal, tungsten. and glass electrodes. The last chapter deals with a large mmber of potentiometrie oridation-re- duction reactions.

The writer wishes to commend the authors' er- tension of Si5ensen's 9~ (the ion exponent or negative log of the h~drogen-ion mncentration) to ions other than hydropen. An excellent bibli- ography is included in this work, as well as rather full tables of normal potentials, ionization eon- stants, solubility products, etc.

I t is to be regretted that the table of normal potentials (taken from No. 8 der Abh, der Deutrehen Bunoenpesellrchaft. 1918) war not amended according to R. H. Gerke's "A Summary of Electrode Potentials." Chcm. Rm. 1, 377 (1925). as the latter will appear in the Inter- national Critical Tables. However, the differ-

ences are, in most -3, small. For -me workers, literature references to the valuer given in some of the tables might prove helpful oc. casionally, although this can scarcely be called a eritidsm.

In conclusion, the writer feels that he has made a most useful addition to his library, and he is sure that teachers, advanced students, and practical workers ail1 agree.

MALCOLN M. H ~ m c

Iotrodvction to. Theoretical Physics, Vol. u. A ~ T H U R HAAS, Ph.D.. Professor of Physics in the University of Vienna. Trandated by T. Verrchoyle. D. Van Nostrand Co., New York, 1926. 1 + 414 pp. 22.5 X 14 em. $0.00.

This volume deals with that part of the field of theoretical physics not covered by the prr vious volume. See Tms Jooma~, a, 710 11925). ~.~

The author has succeeded in these two volumes in presenting a comprehensive survey of the whole field of modern theoretical physics in a compact, concise manner. H e has done much to meet the need felt by all interested in physics, either di- rectly or indirectly, of acquiring a knowledge of the experimental contrihutioo. made to the pbysieal sciences in recent yearsand an intelligent understanding of the theories predominating in that field. The subject-matter is admirably me. sented, clearly and lue id l~ written, each step developed without omissions, without eonfudne the reader by the ure of roml>hcafed and awe- rome marhcmsfrcal r~mbol i and n o ~ m n r . rxhi~h m..v have hithenodrtmrd tbclrvrw~oin O ~ Y I C F I . ~~~~ -->.

The whole compilation shows extreme. oains. . . taking care to render the text readable and underrtandahle for students in any branch of science, all mathematics being expressed in terms of calelllun. A synopsis of the symbols used in the discussion of each portion of the text i. added f n the use of the sfudeof.

These volumes form an ideal basic text either for the prospective specialist in physics, who can use i t as an introduction into any specialircd part of modern physics, or for students in any of the allied science., who are unable to keep in touch.with the correlative work of the pbysickt. These books should prove valuable texts for class "re; affording a proper perrwetiue of the whole

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field of physics. Volume I1 treats of the atomic theory, the

theory of heat, and the theory of relativity. un. der "The Atomic Theory" are discussed the elementary quantum, the theory of the hydrogen atom, R6ntgen rays, the theory of the elements.