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difficult or impossible for the reader to ascertain whether they me based merely on conjecture or aotually a n fact. Insertion of appropriate references would have eliminated this difficulty. Chapters dealing with d i e r e n t i d thermal analysis and X-ray diffraction, as written, could have been eliminated without detracting from the text. Apart from these criticisms we are indebted to Professor Hauser for compiling into a single volume the thoughts of one who has contributed so much to our knowledge of theoretical and experimental colloid chemistry. WILLIAM D. JOHXS W*snrso~ol*U N , V E ~ ~ , T ~ ST. LOUIS.M18soom
THE THIRD DIMENSION IN CHEMISTRY
A. F. Wells, Imperial Chemical Industries, Ltd.
Odord University Press, New 1956. x 144 pp. 101 figs. (some stereoscopic) 6 tables. 1 5 X 22 Em. $3.40. York,
+
IT1s safe to ~ a that y until recently a t least 95 per cent of a chemist's work and thought dealt with the behavior of "molecules." The system8 with which he worked were disordered ones: gases, liquids, solutions. Their very disorder favored the reactions in which the chemist was interested. Linear equations and two-dimensional drawings with only a limited concept of depth were adequate to interpret the reactions and the properties of the reactants. The third dimension sheet. Each year, however, the desirability of understanding the properties of crystals increases, and the amount of fundaments1 knowledge comprehensible only through some knowledge of their structure hecomes lareer. Solid state and surface more depth. Mr. Wells has done us a service again in making it easier than ever before to gain insight into the geometrical problems of the solid state. His style is lucid, his illustrations apt, and his demands on a mathematica.1 background not too great. I t is true that there is little new in this book, except the approach, hut it is just this synthesis that should fill the gap, heretofore unbridgeable for most of us, between crystallographic treatises and chemical structures. Six chapter-Polygons and Plane Nets, Polyhedra, Repeating Patterns, The Shape and Symmetry ai Crystals, Ions and Ionic Crystals, and Finite and Infinite Molec u l e s o f roughly equal length start with simple geometric principles, and apply them to natural phenomena, such as the arrangement of leaves on plant stems, scales on fir cones, wallpaper patterns, and crystalline materials. I can think of no undergraduate course in chemistry (Continued on page A519) JOURNAL OF CHEMICAL EDUCATION, NOVEMBER, 1956
