THURSDAY, JULY 1, 1915. PHYSICAL, CHEMICAL, AND ENGINEERING CONSTANTS. Tables Annuelles de Constantes et Données Numeriques de Chimie, de Physique et de Technologie. Volume ii., Année 1911. Pp. xl+759. Price 28s. 6d. net. Volume iii., Année 1912. Pp. lii + 595. (Paris: GauthierVillars et Cie.; London: J. and A. Churchill, 1914.) Price 28s. 6d. net. THES HESE volumes are a continuation of the chemical, new annual tables of physical, chemical, and engineering constants, the publication of which was commenced by an influential International Committee in 1910; they contain the data for the years 1911 and 1912 abstracted from a very large number of scientific periodicals. One of their most commendable features is that memoirs are not passed over even when their titles do not indicate them as sources of new constants. The abstractors have indeed no light task in the collection of the large amount of information constituting in a single volume the results of a year's research by the laboratories of the entire world. While the basal language of the book is French, the preface, headings to the pages, and the excellent indexes are also printed in English, German, and Italian. When the first volume of these "Tables Annuelles" was published one was inclined to look forward with dismay to the prospect of being obliged when requiring a physical constant to search for it not only in some general book of tables, but in a series of volumes, increasing in number each year. But during the short time which has elapsed since their publication, they have become indispensable to every well-equipped science library, it being understood that their use is supplementary to that of one or more of the standard works of reference. It may be of interest to point out that since the issue of vol. i. there have been published of works on physical constants the large work of the late Mr. CastellEvans, the useful small book of Kaye and Laby, and the fine volume issued by the Société Française de Physique, edited by Profs. Abraham and Sacerdote; also a new edition of "Landolt and Börnstein," more bulky than ever, and two new editions of the well-known Smithsonian Tables, in the last of which the rather numerous printer's errors occurring in its predecessor have been corrected. The two volumes under review bear signs that the experience gained by the compilers has enabled them to introduce a number of improvements, and a careful examination of the books has revealed only comparatively few errors. One of the latter is that experience with an electrically heated salt-bath, employing a mixture of KC and NaCl, indicated that Mr. Dutoit's figures on page 518 of vol. ii. for the conductivity of these mixtures at the higher ranges are given a hundredfold too great; Kx 108 at the head of the column should apparently be K × 10o. The staggering statement on page 408 of the same volume that Cambridge tap water contains 135 × 1012 grams of radium per litre would, if true, delight the heart of many others besides Sir J. J. Thomson and Mr. Satterly. Obviously 1012 should be 10-12. A list of a few other inaccuracies has been sent to the compilers. In spite of these almost inevitable slips we have little fault to find with the volumes, the general usefulness of which is undoubted. In vol. ii. the division relating to spectroscopy, consisting of more than 150 pages, is unusually complete. No fewer than 30 pages are devoted to the Zeeman effect alone, while the results of the work of King, of Duffield, and of Rossi on the effect of pressure are tabulated in detail. In vol. iii. the ground covered seems to have been still further extended, large physiological and biochemical sections being added. It would not, however, be safe to presume that though one finds on page 488 "Lait-Densité 1'027010326" the heading a few pages later, "Propriétés des Laitiers" (page 530), implies that the milkman also has been included. The volumes indicate how great is the progress now being made by research, and render much otherwise difficultly accessible material very generally available. The compilers kindly offer in the preface to vol. iii. to place their services at the disposal of readers requiring further information as to data in periodicals to which they have not access. In view of the necessarily bulky character of these volumes an excellent innovation is the issuing of a number of the more important sections of vol. iii. in separate parts. A reader can thus acquire the advantages of possessing the data on the portions in which he is specially interested, without being obliged to buy the whole work. In conclusion, we venture to hope that the idea of the committee of issuing every five years or so a critical summary volume, in which an attempt will be made to sift out the wheat from the chaff and assess the relative value of the various discordant determinations, will not be lost sight of. The need for it becomes continually more apparent. J. A. HARKER. ELEMENTARY ZOOLOGY. By Dr. Third (1) Zoology: An Elementary Text-Book. (1) A two pages for the inclusion of a necessarily imperfect sketch of recent work on heredity. The (2) Indeed the writers of comprehensive modern text-books must be constantly faced with the question whether it is better to discuss some subject imperfectly or to leave it alone altogether. Profs. Kellogg and Doane have, with considerable success, attempted, within the limits of a handy volume, to furnish their students with a guide not only to the facts and principles of zoology but to its applications to hygiene, fisheries, agriculture, horticulture, forestry, and stock-raising. What may be called the general zoological sections of the book are often sketchy-as where the development of the Mammalia is dismissed in less than a page and the student is told that there is no placenta in marsupials. But there is much trustworthy information pleasantly given, the examples being drawn mostly from North American species. concluding portion of the book is devoted to economic subjects, and there may be found accounts-good though brief of harmful protozoa, insects, and arachnids, with the means to be adopted for repelling their attacks. The authors might perhaps have used the space at their disposal more effectively by expanding this section to fill the whole volume, leaving the student to get his general facts from existing books, of which there are surely enough. Yet a chapter of twelve "" 'Animal Life and Evolution" is a pages on have wonderful example of what can be done in the way of packing a surprising number of valuable facts and suggestions into a small compass. might indeed be defined as might indeed be defined as a sample of "comG. H. C. pressed biology." NEW edition of "Shipley and MacBride" will receive a welcome from students and teachers of zoology, for the original workpublished in 1901-took at once a distinct place among text-books on account of the freshness and individuality of the authors' method. The present volume exceeds in length its forerunner by 100 pages, and many improvements have been introduced. For example, the groups of the flatworms, nemertines, rotifers, and nematodes have been brought from their former position at the end of the volume following after the mammalia, and placed before the annelida. The arrangement, which startled readers of the first and second editions, was intended to emphasise the authors' opinion that these groups are not cœlomata, and this opinion is still set forth, perhaps too dogmatically, in the clear "Introduction to the Cœlomata" that precedes immediately the account of the annelids. The authors accepted Goodrich's distinction-now familiar to zoologists-between true nephridia and cœlomoducts (such as the excretory tubes of arthropods, molluscs, and vertebrates). They also revert to the "orthodox" interpretation of the mammalian ear-ossicles, and in connection with this problem supply a valuable diagram of the temporal region of the skull in theromorphous reptiles for comparison with the mammalia. The book still neglects, to a great extent, palæontological as well as embryological facts, but these are invoked It ECONOMIC GEOGRAPHY. THE where questions of morphology and relationship synonym for careful draughtsmanship are discussed. Indeed, the last half of the volume comprises an excellent introduction to the comparative anatomy of vertebrates. As regards systems of classification, there is always room for differences of opinion, but we believe that most students of the Mollusca will object to the removal of the Chitons from association with Chatoderma and Neomenia, and their replacement in the Gastropoda; while among the arthropods, the unnatural group of the “ Myriapoda" is still retained, and appears in the same class with the insects and the peripatids-an altogether indefensible association. The introduction has been lengthened by a and artistic colouring, and the "Atlas of Economic Geography" is not only no exception to the rule, but also a marvel of cheapness. Prof. Lyde as joint-editor is responsible for the selection of the maps, which are intended to illustrate mainly world and continental distributions. So far as they go, the various maps and diagrams make up a valuable collection. The generalisation necessary for such small-scale maps has been on the whole successful, except in the case of gold, the colour for which is much too liberally distributed. No attempt has been made, however, to distin guish on the map of Europe between major and minor industrial areas, and the absence of largescale economic maps of the countries of Europe distinctly handicaps the atlas for purposes of advanced study. Prof. Lyde has also contributed an introduction, which contains a large amount of both information and speculation. The prefixing of a lengthy and highly didactic introduction to an atlas intended for general university use is a somewhat new departure from well-established precedent. The presence of such an introduction tends to embarrass the teacher, who in this case may possibly differ from Prof. Lyde both in matters of opinion and in methods of teaching. A brief description of the plates of an atlas may at times be useful, but the proper place for all controversial matter is in an accompanying handbook which need not necessarily be placed by the teacher in the hands of his students. An atlas should be concerned solely with facts, to the ultimate arbitrament of which a teacher may refer all matters of opinion. There are two methods of teaching economic geography as a university subject. One is to make certain general statements, and then to proceed to illustrate them by reference to the distribution of certain commodities and industries. The other is to begin with the distribution, and after due consideration of all the facts to attempt a theoretical explanation. Since many of the socalled principles of economic and anthropo-geography are by no means demonstrated, the latter method would at present appear to be preferable. Prof. Lyde, however, evidently believes that better results may be obtained from the former. Hence his introduction abounds in picturesque and suggestive ideas which the student is encouraged to believe may be verified by a careful examination of the facts of production and distribution. For example, it is stated that the ideal climate for wheat is of the Mediterranean type, while as a matter of fact the maximum yield per acre, which, in the absence of any other universal criterion, may fairly be taken as an indication of climatic suitability, is found in a region the climate of which is not usually classified as Mediterranean. Again, the climatic control of the distribution of textile industries, emphasised in the introduction, has long been one of the pious beliefs of economic geographers. It has now become customary to limit the application of this so-called principle to the manufacture of only the finest goods, but the necessity of introducing such a limitation should be sufficient to put teachers on their guard against making any categorical state ment upon the subject. To state in advance and with authority the conclusion which should be drawn from a study of certain regional and economic facts is an insidious method of giving what may be an unfortunate bias to the undeveloped mind. J. D. F. SEWAGE PROBLEMS. Sewage Purification and Disposal. HOSE who accept the conclusion of the THO author that "Sewage purification is the outcome of the activities of bacteria mainly, but assisted by chemical and physical actions, and the purifying agencies of various algæ and water plants," will probably consider that only in a limited degree does this book fulfil the claim of the editors of the series to present the latest scientific and practical information upon the subject with which it deals. Consideration of the biological aspect of the problem is comparatively brief and superficial, and the author is of opinion that "It does not come within the province of this book to touch more than briefly upon chemical points." The outlook is that of an engineer, with extensive rather than intensive experience of the problem; the treatment descriptive and intelligently empirical rather than scientific, but within these limits the book is an informative account of present-day practice. The difficulties, both quantitative and qualitative, of the sludge problem are kept well before the reader's attention, and it is realised that circumstances may justify the discharge of appreciable quantities of suspended matter on to suitably designed filters, with the view of effecting the separation of a large proportion of the inevitable solid matter in its least objectionable form. The entire failure to recognise the significance of the Dibdin slate bed, in this connection, is somewhat remarkable. Probably the most useful sections of the book are those dealing with conservancy systems, and with land treatment, in both of which a clear conception of actualities is presented. The references to foreign practice constitute a valuable feature, and in certain sections, as, for instance, those dealing with the influence of tank velocity upon the character of the deposit, either of detritus or of the main bulk of sludge, might with advantage have been extended, since English practice, as interpreted by the author (in dealing with the construction of detritus tanks, for example, "from 1/100th to 1/200th part of the total dry weather flow of sewage is, perhaps, a usual capacity provided "), affords such uncertain guidance upon important details of works design. Neither practical nor scientific value can be attached to Table XV, "Showing the dimensions of several septic tanks in use in England," or to the bald statement that circular tanks of the Dortmund type are in use, as septic tanks, in the absence of comment as to the suitability of the design to the object in view. The comparison between contact and percolating filters is carefully, and on the whole fairly, drawn, although it is not quite clear whether the working costs quoted are strictly comparable. Assumption of the colloidal form is so characteristic a property of fæcal matter that the author's belief that the colloidal matter of sewage is derived in great measure from soap would seem to require some definite experimental support or reconsideration. The book is well indexed, and is provided with a useful bibliography. PERCY GAUNT. the people are interested in the results which mean so much to the country, for it is from the soil and its living products that the permanent sources of wealth of a community must, after all, largely depend. Prof. Coulter deals with the various methods of raising new and valuable plants, of conserving what has been obtained by the application of rational, and therefore truly scientific, principles which enable disease to be successfully fought, and by which further improvements are to be secured. He also deals with the more outlying topics of forestry, the soil, search for new plants, the work of experimental stations, and so on, and he may be congratulated on the production of an interesting, instructive, and readable volume. We note a few points in connection with which a future edition will, perhaps, afford an occasion for modification. The lettering of the figures on p. II is omitted; and surely Figs. 15 and 10 should not be quoted from the text-book of which Prof. Coulter is joint-author, but from the original source, i.e. from Bonnier's admirable paper on the effects of habitat on plant structure. Exception might well be taken to the illustration on Fundamentals of Plant-Breeding. By Dr. J. M. p. 5 of fluctuating and constant variation, on the Coulter. Pp. xiv + 347. (New York: ground that the potato tubers quoted are the Appleton and Co., 1914.) Price 6s. net. result of vegetative, and not of sexual, reproROF. COULTER is entering the ranks of duction, and the illustration itself also strikes one THE PRODUCTION OF NEW VARIETIES D. PROCES as he already has a place amongst those who The author has skimmed over many difficult and debatable matters with a freshness and vigour of expression which makes his book a pleasant one to read, and he has contrived to weave into the text a very considerable amount of theory and fact. Even those who are tolerably familiar with the work of plant breeding will probably find much that is of interest in what we might perhaps describe as the more remotely relevant matter. The book is, of course, written from the American viewpoint, but it is good that people in this country should have brought forcibly to their notice the supremely important problems that underlie so much of scientific agriculture, in which an immense amount of capital is invested. The Americans take these problems seriously, and This as having an air of unreality about it. A serious The Earth: xi +371. OUR BOOKSHELF. Its Life and Death. By Prof Translated by E. W. Barlow. Pp. (New York and London: G. P. Putnam's Sons, 1915.) Price 7s. 6d. net. PROF. BERGET has written in popular terms a physical history of the earth. He has endeavoured to discern the mode of its origin and to estimate its age, to describe the phenomena of the present living globe, and finally to forecast the manner of its death. He has certainly succeeded in rendering many difficult lines of reasoning clear and intelligible to the general reader. The book is in no part dull, and would not read like a translation were it not that English equivalents As are added after all measurements in metres or in centigrade degrees. Besides the translator's interpolations, an unnamed editor has inserted in the text many notes which would have appeared more appropriately at the foot of the page. these notes are on astronomical points only, they leave the impression that other subjects stand in similar need of amendment, and there can be no doubt that this is the case in more than one chapter. Sometimes the author writes with a little too much confidence. He treats a theory almost as if it were a scientific fact. For instance, he refers to the contraction theory of mountainformation as though its foundation were secure. He accepts as proven an eleven-year period of earthquake-frequency and the increased frequency of earthquakes at the times of the equinoxes. While reading the book, it is difficult to resist the impression that the author does not always trust to original authorities. This impression is perhaps strongest in the chapter on seismic phenomena, in which, though the original text must have been written in or after 1909 (see p. 208), many facts are omitted which should have found a place. Indeed, in this chapter of thirty-eight pages, the name and work of Milne are never once mentioned. A Map of the Western War Area. Edited by Prof. A. J. Herbertson. 60 in. x 60 in. (Oxford: The Clarendon Press.) Price, mounted in sections, with names 158., without names 12s. 6d. THIS useful and striking map depicts the country from the Seine to the Rhine, and from the Swiss frontier to the Rhine delta, on a scale of eight miles to 1 in. (1: 500,000). It is provided with contour lines and layered colouring, and shows vividly the interdependence of land relief and military strategy. It is issued in several formsunmounted, mounted in sections, and mounted on rollers, varnished or unvarnished, at prices varying from 10s. 6d. to 17s. 6d. Produced under the supervision of Prof. Herbertson, it provides an excellent and trustworthy companion for the student of current events in France. LETTERS TO THE EDITOR. [The Editor does not hold himself responsible for opinions expressed by his correspondents. Neither can he undertake to return, or to correspond with the writers of, rejected manuscripts intended for this or any other part of NATURE. No notice is taken of anonymous communications.] A Canadian Memorial to Hugh Miller. In a letter which I have just received from Dr. John M. Clarke, director of the State Museum at Albany, N.Y., he writes:-"You may be interested to know that at my urgent suggestion the Geographic Board of the Province of Quebec have adopted the odd that the devout French Catholics of P. Quebec should consent to this naming of their scenery after a Scotch Presbyterian, but the cliffs look across the bay from French Quebec to Scotch New Brunswick!" Geologists in this country will be pleased to hear of this Transatlantic recognition of Miller's pioneer work, and they will feel that Dr. Clarke, who is familiar with the classic Cromarty ground, as well as with that of Scaumenac Bay, deserves our thanks for suggesting this unusual but most appropriate memorial, and for his successful efforts to have it carried ARCH. GEikie. out. Shepherds' Down, Haslemere, June 24. The "Green Fluorescence" of X-Ray Tubes. THE Glass Research Committee of the Institute of Chemistry has recently issued a note on the conditions for obtaining green fluorescence under kathode rays in glass suitable for X-ray tubes indicating that the presence of a small amount of manganese must be present. In view of the fact that there appears to be some misconception regarding the necessity of the green fluorescence it may be of interest to give a brief account of what is involved in obtaining as marked a fluorescence as that which has usually been noticed in working X-ray tubes hitherto. So far as I am aware the advantage of the green fluorescence is that it provides the X-ray operator with a convenient rough indication of the hardness of the tube. It is scarcely necessary to point out that the quality of the X-rays is in no way influenced by the nature of the fluorescence of the glass. Experiment has shown that a strong green fluorescence can only be obtained at some sacrifice of the excellence of the glass. Glass manufacturers frequently add manganese dioxide to a glass mixture to correct the green colour due to iron which is invariably present to some extent in the ingredients used, and, of course, the more iron there is as an impurity the more must be the amount of manganese dioxide added. Thus in some cases, in order to obtain the full green fluorescence, an appreciable quantity of iron must be added to relatively pure ingredients so that the necessary quantity of manganese may be incorporated in the glass, the iron being needed to correct the amethyst colour which so much manganese would otherwise impart to the glass. This procedure appears to impair the working qualities of the glass to some extent, and it is found that glass of a quality superior (in respect to its behaviour in the flame) to that usually employed can be made if iron and manganese are avoided. A few experiments may be mentioned in support of this statement. Glass made from pure materials shows practically no fluorescence, the feeble glow being of a grey-blue colour. A Rupert's drop made from the same glass gives a similar feeble glow. A Rupert's drop made from glass giving normally a strong green fluorescence shows only a slight greyblue glow. After the tail of the drop had been heated to softening point this part showed the usual green glow. In a high vacuum under very intense bombardment there was an indication of some slight green glow on the drop. The drop was broken and the powdered glass gave the full green glow. The evidence was that only a very thin skin represented the part cooled quickly enough to give next to no fluorescence. Calcium silicates of varying composition containing a little manganese, which were fused by the oxyhydrogen blowpipe, showed on the outside portions, which appeared to be completely vitreous, no |