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BOOKREVIEWS
complete coverage will arise because of t h e question of the meaning of t h e term “concentrated solutions.” T h e author states t h a t “As concentrated solutions I choose t o consider arbitrarily systems between 10 and 90 per cent by weight; I left also out of consideration d a t a relating t o dilute solutions, if there is only one measure between 10 and 20‘;;.” This is not altogether clear. While i t suggests t h a t t h e tables would give no d a t a outside t h e range 10-90%, there are actually very many tables covering very low concentrations a t one or both ends of a system. When such information is not given, the reader will not know whether i t was omitted according t o plan or whether the literature contains no such d a t a . M a n y of the systems are covered in great detail, while sixne are given with just three points, the pure components aud one binary point, as for the over two thousand azeotropes cited from Lecat’s book (1949). ( T h e rest of Lecat’s (j287 azeotropic systems will presumbli- be included in t h e subsequent volumes, b u t Lecat’s information on “7eotropes,” altogether 7003, seems t o have been ignored. .Is a mechanical compilation this is quite unlike a n y other czllection of numerical d a t a , in t h a t there is no averaging, no critical selection, of values. It simply presents t h e numbers as they were originally published. T h e densities of benzene-toluene solutions, for example, appear in nineteen consecutive tables, sonic long, some short, from the year 1896 t o 1956. T h e author adds no comments on relative dependability, and the number of “significant figures” is left as in t h e original papers. T h e density of benzene itself, for just 2 5 O , appears about 100 times in tlie Volume, many o f the entries being from the same source. They ccver it range from 0.8696 to 0.87661 (in one case 0.871651, from 1919). :here are also t h e values 0.86035 and 0.8617; these are not sports,” however, but t h e result of the reversal, either of order or of meaning, in the composition column. T h e range almost overlaps t h a t for t h e density a t 20°(about 70 entries): 0.8760 t o 0.8809, not counting one value, inexplicable, of 0.8710, and including 0.878434, from 1910. Personally I think t h a t this is not as valuable as would be a compilation of selected data, a thing which Dr. Timmermans undoubtedly could have done with ability and authority. B u t it would not have been possible without much more help than he used. And there will certainly be those who will appreciate what he did do. I t is somewhat like scanning the original articles themselves, at least for tlie results reported in them. Some of t h e older items are hardly inure than of historical interest. In some cases the mass of figures tabulated would require quite a labor of plotting t o deduce the “phpsico-chemical constants” which they detcrmine. This is the case with the pressure-volunietemperature-conceritration d a t a for t h e liquid-vapor relations of the system benzcncether, ,given in two tables, one from 1881 and an extremely extensive one from 1908. A more or less careful perusal of the tables has revealed certain occasional faults. In a few cases, some symbols or functions are not adequately defined, and i t is consequently not clear what relation is represented by t h e numerical ralucs; this happens a few times for t h e symbols C, CI, CZ, meaning a solid, uiidefined, in certain complex phase relations involving liquid inimiscibility and liquid-vapor critical phenomena. Symbols are occasionally confused, such as p ( = n i t i i . j and 1’ ( =:ttm.). X condition such as the ternperature is sonietimes omitted. Sonic numerical values :ire wrorig, iis seeii simply from t h e break in trends. By ironic :teeidelit, the very first page o f the book has s i m e strange things. T h e opening table gives diffusion coeDicicnts in the system “methane (CHI) tritiumnicthane ( CH3T),’:; b u t these were simply measurements made with tritmm-tagged methane, and one could hardly be farther from “concentrated solutions” even with reagent grade materials. T h e third table, still on page 1, gives liquid\Tapor compositions for methane-ethane; t h e figures looked strange, and it turns o u t t h a t “yo” (to be understood throughout t h e book as referring t o the second component, here ethane) should be ‘‘yo methane,” and t h a t all t h e temperatures listed (Centigrade) should be negative. T h e fourth table on p. 1 (extending to page 2), for the same system, also has strange looking figures; nine of t h e numerical values were either niisciipied from t h e original or spoiled in printing. There are a few more errors on pages 3 and 3 , including confusion between weight a n d mol 70in both Table -5 and Table 6 . This checking takes time, because, t o repeat, the bibli
