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cement and plaster; one on ceramic products; and one on glasses and glazes. The subject of glazes is a fascinating one which will certainly be taken u p by the physical chemist some d a y and then lie will find the information in this book of great value to him. I t is xell known t h a t the high price of artistic potteries is due in part to the uncertainty of the process, the number of successful pieces being relatively small. This is merely the result of doing things in a haphazard \my without paying careful attention to the temperature and to the composition of the gases in contact with the ware. Some day these things will be run as they should be and then we shall hear much less about the itnpossil17ilder D . Baricroft bility of controlling conditions. Tables and Diagrams of the Thermal Properties of Saturated and Superheated Steam. By Liolzel s. .\larks a n d Harzey S.Dazis 16 X 23 cm; p p . IO;. .Ye=) l ’ o v k : Longmaits, Gveen c ? Co., 1909. Price: bound, $1.00 ?set.“ T h e tables of the properties of saturated steam which have appeared up to the present time have all been based upon the classic investigations of Regnault, carried out more than sixty years ago. I t has been apparent for some time t h a t the total heats of dry and saturated steam, as determined by those admirable researches, are belox the correct values. The great difficulty in obtaining steam which is exactly dry and saturated has not been appreciated until very recently; and i t is undoubtedly true t h a t Regnault \vas investigating steam containing a small amount of moisture when he thought t h a t he was dealing with dry steam. Fortunately, the recent investigations of Dieterici, Smith Griffiths, Henning and Joly give a trustworthy body of new values of the total heat of dry steam a t pressures below atmospheric pressure, while the method recently elaborated by Davis, when applied to the throttling experiments of Grindley, of Peake, and of Griessmann, gives remarkably accordant determinations a t pressures above atmospheric pressure. The table which we have prepared is based entirely upon these new values, and is probably correct to one-tenth of I percent within the range of steam pressures usual in engineering practice, Xegnault’s formula gives results which are too high by 18 B. t. u. at 3 2 O F, too low by 6 B. t. u. a t 2jj0 F, and again too high a t 380” F, the error increasing rapidly a t higher temperatures. “ T h e investigations of Knoblauch, of Thomas and of Henning are the necessary basis for a n y determinations of the properties of superheated steam. These investigations have been subjected to a careful analysis, both as to the probable errors resulting from the methods of experimentation, and also as to the relation of the experimental results to the values deduced from thermodynamic theory, so far as this latter throws any light on the matter. &‘here the results of t h e separate investigations are not closely accordant, a critical estimate has been made of the relative values to be given to each, in the region under consideration. The properties of superheated steam are tabulated for every pound pressure, and for every ten degrees of superheat, within a range which exceeds present practice. All the inforination relating to superheated steam of any pressure is given on one double-page, an arrangement which permits the immediate finding of any desired quantity. Supplementary tables extend the superheated steam table to very high temperatures and give the properties of water, metric conversion factors, Xaperian logarithms and other quantities.
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“Beside the tables, we have prepared t\vo large diagrams showing the properties of saturated and superheated steam. These diagrams can be used, instead of the tables, for finding the total heat, entropy and specific volume of steam of a n y known quality or superheat (within a n extended range), b u t their chief purpose is to facilitate certain calculations. In consequence of the variation of the specific heat o f superheated steam with both pressure and temperature, the solution of commonly occurring problems involving superheated steam is either laborious or approximate. If the tables are arranged in such a manner as to aid the solution of problems of one class, they become inconvenient for other purposes. The total heat-entropy diagram. devised by Mollier, makes i t possible to solve immediately many of the problems which arise in connection with either saturated or superheated steam. A total heat-pressure diagram, showing specific \-olumes, permits the solutions of problems involving rolumes. By the use of the t v o diagrams, either separately or together, a large number of the steam problems occurring in the design of engines and turbines, or in connection with the flow of steam, or its throttling, can be solved without a n y calculation. These two diagrams h a r e been plotted with great care from the data given in the tables, and should prove useful to all engineers or students engaged in m a k ing calculations which involve saturated or superheated steam.’’ 1t.ilder D . Bancrojt
