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scverc niathcmatical s t y l r , with very few illustrations of practical applications of the topics discussed. Now i t seems t o US t h a t i n teaching quantum niechanics t o chemistry students t h e dilernma has for one horn the deep prnctration i n t o the subject required t o reach t h e chemical applications, which lie in an advanced rcgioii, and for the other horn the' step-by-step introduction rcquircd b y most chemistry studcnts, \rho conic to thc subject n i t h o u t much helpful background in mathematical physics. JVe believe t h a t the nvcragc graduate studcnt in chcmistry a-ould profit from this t e s t only in connection with n coursc of lectures designed t o expand and illiistrstc t h c material studicd. Hon.cvcr, once .‘led into” t h e subject i n such fashion, the studcnt would, wc belicvc, find this book most vnluable, for it wvould provide him with an introduction t o almost 311 the quaiitum applications of interest to chemists-a thorough introduction from n h i c h hc could Y O on i n t c ~ ~ i g e i i t l y . In this respect we might compare the I)oolc to Joos’s a.t~ll-hiioir-n?’heoretical I’h!jsics, escept for the omission of a n y problems. T o commcnt on a feiv particulars: JVc JTcrc plcascd to fiud a11 carly introduction and f r w use of group theory. This mathematical tool is of great v d u e in ~nolccularproblems: nntl gives generous dividends on l h c little effort required to master its applicatioii. A h ~ t u a l l y i t is less subtlr t,han the calculus-and, likc t h a t tool, can l ) ~ ,easily npplicd t o physical problems even without an undcrstnriding of tlic mat ticmatical f o u n d ~ t i o n s . T h c chapter on reaction r a t r theory is not, conccrnetl u i t h the application of tlic tlicory OF absolute reaction ratcis to c o t i ~ r r t creactions; ~ it prescnts a rathcr cnrcful dcrivation of t h c esprcssiori for the rcaction m t r togcther ivith qualituni-lllechniliea~invcstigntioli o i i t s validity, particularly \\.itti regard to tlic, transniissioii coc,fiic-icnt. The saiiir a1)pro:ivli i; t o he found iii t h e ch:iptcr 011 ,statistical mrrhnnic,?. It is, of coursr, cOfisiStcnt with t h e gcncral purpose of the volume 0 1 1 the ot.hcr Iiand, t h c t.rr:itinciits of niolc.cular c,iirrgicis (hy both tlic nio1ccul:ir orLital and thc Heitlrr-I,oiidori nicthods) and C J f InCJlrCU~alRprctl’:I! li-hilc eomp:ict arc quitc con1pletc. T o suminarizc,, n’o frel that t l i :iiitliors ~ 1i:ive ~ I Y J J U:IC1)ook ~ ~ I n.liic.Ii \r.i]I 1 ) a~ valuablcb and welcome addition to tlic boolishrlvcs of physical chcniists, and ~vliich,when supp1enienteti hy illustrative l w t u r c s :ind p r o \ ) l c . i i ~s~l ,i ~ i i l t lninlic~a sound t c s t for L: thorough coursc in quantum clic~mistry. I~RTCI: T,. CRAWFOHD. JR.
H?/rli,ogenI o n s , ?‘heir lA?te?niinal?‘on n ? d f t n p u , ~ l a r i c ei7i Pui c uftd I?idusli.ial C h e m i s t r y . By 11. T. S.BRITTON.Third cditioli. Tn-o volumcs (420 ant1443 p p . ) . S c w T o r k : I). 1-311 Sostrand Company, Inc., cui point OF vie\\- JV. 31. Clark’s clarbic From t h e therniodynamic treatise, ?‘he I)efe?mz’nation 0.f H?jdioge?i Tons, is still tlic most rxact onc among thc many ~ v nis of a some~r~llnt texts which ha^^ l ~ c rvriltcii n on the s u h j w t . 13rittori’s t ~ r l l - l ~ ~ i ohook diflercnt nature. Although the first volunia ( l e a k mainly n i t h the thcory and methods of detcrmining hydrogen-ion roncc~iitration,thc main cnipllasis is placed on thc p a r t playetl by hydrogcn ions in chemistry and i n numerous tcchnirnl processes ( ~ o l u ~ n11). c ~ The author’s viewpoint is reflected in the Preface : “25s niuch of thcx fundamental ir-ork on hydrogen ions was carried o u t beforc the activity thcory of clcctrolytes had gained n i d c ncccprnnce, a n d as the clcctroinctric dcfcrminations of p I I a r c usu:illy niadc with cells in n-hich 11 the modern theory is not strictly applicablc~~ t h e theoliquid junctions exist a n d t o .F.of such cells, given ill thc cnrlicr editions, h a s Lreli retical interpretatioii of‘ the retained. To some, this proccdurc niight appear unjustifiablc, b u t the fact must not be lost sight of t h a t the activity theory c a n only he rigidly applied t o cells without transport, i.?., vi t,hout a liquid junction, which typc of rcll is scarcely evcr used for ordinary pH tlcterminntions. Whatever may h r the true meaning of thc pII value, there is no doubt t h a t p H values will remain a n invaluable means of accurately assrssing the extent of the acidity or t h e alknlinity of a solution.” Granting t h a t the exact value of the hydrogcn-ion activity of a solution \rill be f(Jr(’Vrr rinknon-ii, it may be stressed t h a t in many instanccs this value cnn
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he measured with a close approximation, even though the tn-o half-cells containing different electrolytes are connected by a salt bridge. Most of the d a t a in t h e first volume are based o n the o u t d a t e d assumption t h a t conductivity d a t a i n hydrochloric acid solutions yield the true concentration of hydrogen ions, although later i n the same volume (pp. 253-29.1) the activity theory of solutions is discussed. It seenis t o the reviewer t h a t i t ~ o u l dbe preferable to base the entire discussion on the modern theory of electrolytes and t o interpret the older d a t a in the light of the niodern ld viens. -1more critical presentation of standard potentials of standard half-cells ~ ~ o ualso be desirable (compare, e.g., Table 4 , p. 29; Table 7, p . 36; and Table 48, p. 263). The values of K, given in Table 9 (p. 53) are n o longer accepted as accurate; they could be replaced by inore modern d a t a . I n the above the reviewer has emphasized what he considers t o be the most outst,ariding weakness of Britton’s extremely valuable book. I t is adniittcd that every author of a book on the determination of the hydrogen-ion (or any other ion) activity csposcs himself t o criticism, since its ezact deterniination is a physical impossibility. A11 approzininte determination is possible, and the approximate value obtained is of such importance in pure a n d industrial chemistry t h a t a compromise betn-ecn exact theory and approximate measurements is more than justified. T h e previous editions of Britton’s book are s o ne11 known and have served so many people engaged i n “pure” and ‘;industrial” research t h a t the new edition hardly needs a recommendation. The present two-volume edition is even more mluahle t h a n its predecessors; i t is not only brought up t o date but i t also contains several new chapters not found in previous editions. T h e inorganic chemist viill be n-ell pleased irith the various chapters in Volunie I1 dealing with the fundanieiital importance of pH in inorganic chemistry. (The chapter o n sulfides could be made more complete. j Chapters dealing n-ith the importance of pH in leather manufarture, tanning. sugar manufacture, brewing. mill;, hen’s eggs, baking, Tvater, soils, ceramics, and textile and d y e industries cocclude the second volume. I n connection n-ith the chapters on milk, eggs, halting, e t c . , the introduction of a few eoricisc chapters dealing with the significanre of pH in enzymology (and in biochemistry in general), physiology, and bacteriology would make this important book still more useful t o a wider circle of scientists. I. 11. KOLTHOF‘F.
