JOURNAL OF CHEMICAL EDUCATION
402 give. The lad-length curve of polyvinyl chloride shows such plastic behavior, and h u m hair responds to load as does polyvinyl chloride. Two theoreticslly possible elastic power cycles are next discussed. These are the potential enerm cycle and the entropy (kinetic) cycle. Several conceptions of potential energy cycles are given and the difficultieswhioh arise in applying these to muscle contraction are stated. The entropy cycles are given as (1) a heat engine analogous to a Carnot cycle and (2) a ehemical engine in which the attractive forces between molecules are controlled chemically. To obtain information on the nature of the power cyele in biological systems the dynamic modulus is considered by the author to be of value. This modulus is obtained by subjecting the system under study to a rhythmically varying load. The dynamic modulus varies with the frequency of load variation and this response to frequency yields valuable information about the properties of the test system. The author first pictures and describes his own apparatus for the measurement of the dynamic modulus and then gives some of his own results on a model system consisting of pheasant leg tendons contracting when treated with a solution of potassium merouri-iodide. The last section of this chapter deals with muscle. The author review8 previous work and the results of his own experiments as to the effect6of stimulation on viscosity and the variations of the dynamic modulus with frequency. The conolnsion is reached that the kinetic theory offers a more reasonable concept of the behavior of muscle unless one wishes to add additional complications to the potential energy hypothesis. Muscle contraction is thenvisualized as a change of the musole proteins from the resting state, when they are in a semicrystdine condition or when intermolecular forces are high, to the sctive state when there is a decrease in the forces binding protein chains and a reduction of the orientation. The immediate stimulus for this change is assumed to be the addition of a plasticieer-perhapa ATP-which reduces the intermolecular forces. Recovery of the orientated state is assumed to follow upon the enzymatic destruction of the ATP. FREDERICK CRESCITELLI Umvrnsmr OP CALTWRNIA Los ANWLEB. C A G ~ O R N I A
WATER TREATMENT Eskel Nordell, Administrator, Analytical Labratories, Research and Pilot Plant Divisions, The Permutit Company. Reinhold Publishing Carp., New York, 1951. vii 562 pp. 126 figs. 162 tables. 16 X 23.5 cm. $10.
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Trrod~who arc intcrritd i l l the incluitrinl trcatmetrt of water will find tlrk book to he of great pravtival v d w . Every p h ~ of e inrlusrrial trcarmrmr 1s rouehrd upm. Tlw ~rinriplr.;involved in the various processes are clearly explained and the standard industrial practices are so completely covered as to leave little more to be desired. There is a well-selected bibliography a t the end of each chapter. Many definitions, equivalents, conversion factors, and tables are arranged in 28 pages of appendix. There are 18 chapters whioh cover source and character of supply; the nature and significance of impurities present, whether dissolved minerals, gases, turbidity, or mioraorgmisms; water requirements m d type of treatment required for various industries; boiler feedwater practices; chemical feeder characteristics; removal of suspended matter, turbidity, and color; coagulation and filtration; methods ot iron, manganese, and silica removal; softening and demineralizingmethods. Many water analyses are tabulated to illustrate the wide varis, tions in quality of sources of supply. These andyses have been recslculated so that all constituents, even to nitrate and bromide, are expressed as calcium carbonate. The tables of conversion factors in the appendix will be welcome to many who will wish to think of nitrate or bromide as such rather than their equivalents of calcium carbonate. One wishes that space had been devoted to methods of analysis for constituents other than dissolved
gases. The titration method for determining free carbon dioxide is given in detail. In view of the importance of pH in relation with water treatment problems some discussion of this would have been desirable. The chapter on water requirements and necessary treatment for various industries is very complete. The classified listing of water-treating equipment and types of equipment used in various industries will he valuable not only to students and oonsultmts but also ta engineers of city water departments. Chemical feeders are classified and each type of machine is described along with its advantages and limitations for the jab to he performed. The basic principles of coagulation are discussed as well as the properties of those chemicals used as coagulants. The zeolite process of softening is quite complete. This is followed by an excellent discussion on hydrogen-cation exchange and demineralizing processes including mixed bed deminerslization. Both hot and cold limesoda softening processes are described, from early conventional methods to the newer catalyst methods. The final chapter on silica removal will bring the reader up to date in important methods of treating watprs for high-pressure boilers.
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ANALYTICAL CHEMISTRY OF THE MANHATTAN PROJECT
Editor-in-chief: Clement 3. Rodden, New Brunswick Laboratory, U. S. Atomic Energy Cornmiasion. McGraw-Hill Book Co., Inc., New York, 1950. xx 748 pp. 151figs. 68 tables. 16 X 23.5 om. $6.75.
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THEwartime Project made unusual demands upon its analytic d chemists. Not only were many of the rarer elements studied with a new intensity and in novel combinations, but trace concentrations of all sorts acquired a new importance because of the high neutron absorption cross section of many otherwise harmless contaminants. The whole anslytical literature of such elements as thorium and uranium was most thoroughly sifted and in this book has been largely rewritten as a result of Project studies. In the first part of the book about 200 pages are devoted to uranium and thorium and 300 more to the rest of the individual elements. The remaining 250 pages discuss speoial analytical laboratory equipment and techniques. This section is illustrated with diagrams and photographs of special Project apparatus. The book as 8. whole serves as a most useful supplement to such works as Hillebrand and Lundell's "Applied Inorganic Analysis." NORRIS F. HALL
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FLOW MEASUREMENT WITH ORIFICE METERS
Reid F. Sfeorna, Robert M. Jackson, Russell R. Johnson, and Charles A. Larson, Standard Oil Development Co. D. 350 pp. 160 Van Nostrand Co., Inc., New York, 1951. xviii figs. 26 tables. 18.5 X 26.5 cm. $7.50.
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THIS book is one of "The Esso Series" and is primarily directed to engineering, technical service, and instrument groups concerned with process control, test work, and plant start-ups in the petrolum industry. It does a good job of collecting in one book all of the information necessary for the practical application of orifice meters, although the physical data presented are for the most part limited to fluids found in petroleum refking. A number of example calculations worked out in detail may be of intereat to students. 5. RICKLIN
