JOURNAL OF CHEMICAL EDUCATION
196
are quite elementary in their content and provide a basis for more detailed discussions later on. The reviewer must confess E. E. Wohlstrom, Department of Geology, University of Colorado. to a con~iderabledegree of irritation with two items in thib sec408 pp. 178 tion. First, the author gives the formation of hydronium ions as John Wiley & Sans, Inc., New York, 1955. v i i figs. Tables. 14.5 X 21.5cm. $7.75. an example of electrovalency of hydrogen. While hedging his PROFESSOR WAALSTROM has designed his most recent text discussion so as to avoid, in the main, outright misstatements of "for a semester course [in petrography] that would normally fact, the author manages to give the reader what seems to the follow a course in the theory and operation of the polarizing reviewer to be an erroneous impression of the situation. In microscope." The &st five chapters are brief discussions of the particular, the reviewer is unaware of any experimental evidence collection and preparation of rock samples, the separation and requiring the assumption of even the "momentary" existence of identification of mineral and rock samples by various physical free protons in systems of the..type discussed by the author. and chemical techniques, review of the microscopic methods of Second, the author's use of H:CI:-O: as an example of dative examination of minerals and aggregates, the use of the universal covalency, while stating that the structure is more probably stage, and a summary of various methods for the presentation and calculation of petrographic data. The author clearly intends H:O:CI:, seems indefensible. Certainly the author's chemical .. these chapters t o serve only as introductions to most of the snbjects and lists a few well-chosen references a t the end of each experience is not so limited as to force the choice of so qnestionchapter for the student who wishes to pursue some of the topics able an example, particularly in view of the fact that four pages are devoted to the discussion of this probably spurious mole in areater detail. The next three chapters are in the main body of the text. The cue. The second portion of the book contains the chapters: V, general petrographic character, distinguishing f e a t m s and tests, The Wave Mechanical Interpretation of Valency; VI, Metrical and, briefly, the geologic occurrence and as~ociationsare systematically described for the more common rock-forming silicate Aspects of Valency; VII, The Relation between Electrovalency minerals and for the nonsilicate minerals. The last chapter of and Covalency; VIII, Other Types of Interatomic and Interthis group contains lengthy tables for the petrographic identi- molecular Forces; IX, Valency in the Long Periods; X, Caorfication of minerals. Much of this material has been incorporated dination and Hydration; XI, Acids and Bases; XII, Qumfrom an earlier text, "Igneous Rocks and Minerals," hy the same tivalence, the Molecule and the Band. There are in this section author and publisher, but there has been considerable revision a number of instances where the treatment of the material is of and expansion of both individual mineral discussions and the questionable accuracy or is not up t o date. The following paragraphis quoted as an example: c'Oxidation-reduction on the one total number of minerals treated. The final three chapters are inevitably outline presentations hand, and acidity-basicity on the other, are now seen to be closely of the properties, compositions, and classilications of igneous, related, but thev are not identical. The difference is that in the sedimentmy, and metamorphic racks. The brevity of these dis- formerklectroni are transferred [italics are the author's] from the cussions and the descriptive approach make extensive use of the reducerto the oxidizer, whil~tin the latter the base donates a pair selected references for each chapter essential for the student who of electrons but at the same time retains a hold on it, so that a is to become aware of some petrological usefulness for the in- covalency bond is formed." The reviewer wonders how the author would clsasify the following reactions: cluded information, The text is marked by Wahhtrom's usual effective descriptive stvle and it is enhanced hv numerous excellent illustrations. As n lnhorntoty mnnual it wnlainr su impnvuivr quurrriry of 11.i~lu1 infortnntior~for thr introdurtory studcnr. TI,,: veq i r u h i v c la.sr of r l w sthjcct m:rttw incvitsbly ~nakcsthe treatment ul many important topics seem perfunctory, which perhaps cannot he totally avoided in a text a t this level. A more important criticism stems from the absence of any attempt to yive the stuA second example is that in the section entitled, Nature of dent an appreciation of how systematic may he the Linkage in Coordination Complexes, there is no mention of applied to current problems in petrology. Thus, at a time when multiple or rr-bonding, nor is the concept of "inner" and "outer" the nroblems of achievine s a t i s f a c t o ~olassifications of rocks and orbital complexes discussed. There are other such examples. of reconriling genctic \.crsuq dcrcriptivr uppnxwhw aro d r h t r d I t is the reviewer's opinion that because of instances like those \,igorotrcly in t l r litcraturc, ~hcauthorlrnvrr11w studertt ulmware described above and because the treatment is generally so sketchy t h t any other approwhcs nra? exist. Thia rrxt tlwcfmc would as to reduce its value to the student, the book cannot be recomrequire supplementation and cannot be considered sufficient in mended as an "introduction to the electronic theory of valency" itself for s. h a l undergraduate course in petrography and pe- for any except the reader whose interest is highly superficial. troloey. Whether it is desirable for the student to wait for yet another semester and another course to obtain some appreoiaGon HARRY A. BISLER of the importance of petrography to petrology is a pedagogic question concerning which Wahlstrom certainly will find many divergent opinions. 0
PETROGRAPHIC MINERALOGY
+
.. .. ..
LEON T. SILVER C&IROX"~AI N ~ T I TO~f T TECANOLO(IP . Pasaomn. Cafirromr* 0
AN INTRODUCTION TO THE ELECTAONIC THEORY OF VALENCY
J. .C. Speokmon, Senior Lecturer in Chemisby, University of Glasgow. Third edition. St. Martin's Press, New York, 1955. vii
+ 180 pp.
8 figs. 13 tables. 12.5 X 19 cm. $2.50.
THIS is the third edition of a book first published in 1935. It is divided into two parts. The first part (46 pages) contains the chapters: I, The Data and the Principles: 11, Electrovalency; 111, Covalency; and IV, Dative Covalency. These four ohapters
0
COLLEGE CHEMISTRY
Linus Pading, Professor of Chemistry, California Institute of Technology. Second edition. W. H. Freeman and Company, San Francisco, 1955. xii i- 685 pp. 202 figs. 42 tables. 16 X 23.5 cm. $6.00.
INTHIS new edition of the popular "College Chemistry" the beginning onethird has been materially revised. On the one hand a numher of paragraphs have been added designed to give students perspective, and on the other, important ohanges have been made in the text Drooer. These chanees . . - are evidentlv in rrapor.sr to cnnwat and ~)r~cricaI sumstions mndr by teurhrrs wla, hsvr "3rd thr first edition. The r r d t , in the opinion
