The Science of Soap Films and Soap Bubbles
Cyril kenberg, (Editor),Tieto Ltd., Clevedon. England, 1978. ii 188 pp. Figs. and tables. 21 X 15 cm. $20.00.
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If any of you have been searching for a means to bring together some aspect of the intrinsic beauty of the natural world and the formalisms of modern science, I could not think of a more effective vehicle than this recent book on soap films and hubbles by Cyril Isenberg. These fascinating phenomena were first popularized hy C. V. Boys in a baok published in 1890. I t was directed toward youngsters aged 10 to 14, and therefore did not deal with either the molecular or mat he^ matical properties of films. Isenberg's book provides the link between the papular treatment for young people and research texts for workers active in the field. There is a relatively short but adequate discussion of the molecular properties of soap films, along with some recipes and references to preparative details in Chapter 1, the gem era1 introduction. However, the bulk of the introductory material is historical and directed toward the physical and mathematical properties of films. The second chapter explores both macroscopic and microscopic aspects of the draining and thinning of soap films. Chapters 3 and 4 descrihe the application of soap films to the solution of physical problems involving mathematical mini mi^ zation in two or three dimensions, i.e., the soap film as an analogue computer. This is based on the fact that a soap film constrained by a boundary will reach a minimum in free energy a t equilibrium. At this point, the area
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1s also minimized since the film's free energy
Vinyl Cations
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to its area. Therefore, from a practical view it is only necessary to construct the proper constraint (a mechanical device or frame) and to prepare an appropriate soap solution (recipe's are provided), to observe for example the analogue solutions to the Steiner problem (what is the shortest total path connecting n points?). Chapter 5 focusses on the Laplace-Young equation, its derivation and application to problems involvine- caoillaritv of both static and dmamic . systems. In Chapter 6 , the final chapter, a number of prohlems usually solved by digital computers, e.g., normal modes of vibration of fixed shape membranes, are solved by a n a ~ logue methods. Although these solutions are not as precise as those derived digitally, they possess the great advantage of being visual^ ized directly. The appendix contains detailed mathematical analyses supporting the material presented in earlier chapters. There is a good index, an excellent series of color plates, and a rather complete list of numbered references to hooks, papers, and useful pedagogical materials. Although this is probably not useful as a standard textbook, since it is rather specialized and expensive, it will he of real value to those interested in films and their properties. T h e material is excellent far classroom use in physical chemistry and in mathematics as well. I stmngly recommend its purchase for the school library for reference and for sup^ plemental reading. 1s d~reetlvvn,oortional .
Ira Blei College of Staten Island City University of New York New York, NY 10031
Peter J. Stang, Zvi Rappoport, Michael Hanack, and L. R. Subramanran, Academic Press, New York, 1979. vii 513 pp. Figs. and tables. 23.5 X 15.5 cm. $53.00.
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The localization of a formal positive charge on an spZcarbon center remains, I suspect, for most organic chemists a n anachronism for which they are ill prepared by training and experience. This book is a comprehensive discussion of the chemistry of such seemingly unlikely chemical intermediates written by a "task force" of four scientists who have made major contributions to this relatively new but burgeoning research area. In the very brief but valuable introductory chapter (hy P. J. Stang) we learn (a) that vinyl cations were generated as early as the 1870's as reactive intermediates in the acid catalyzed hydrations of acetylenes and allenes to produce ketones, (b) that, in 1944, Jacobs and Searles (at UCLA) correctly postulated the intermediacy of vinyl cations in such acid catalyzed reactions, and ( c )another twenty years passed before detailed mechanistic investigations provided the firm support for this concept which set the stage for the impressive development of related chemistry which the remainder of the baok documents. In Chapter 2, "Thermodynamics and Theoretical Calculations" (again by Stang), the kevauestionsof the structure and enerev *. ... content of vinyl cations is dealt with before proceeding with a series of longer chapters (Continued on page A181)
Volume 58
Number 5
May 1981
A179
