82 



NATURE 



{May 31, 1877 



porated in the work before us. In this first volume of his 

 work the discharge of water is very fully treated. Un- 

 fortunately, however, his so-called theoretical formulas 

 belong to the same category as those which Prof James 

 Thomson of Glasgow showed in his paper, read before the 

 last meeting of the British Association, to be founded on 

 assumptions which are not in accordance with known 

 hydrodynamic principles. 



On page 851 of this translation there is a formula to 

 which we would draw attention. It is taken from " The 

 Lowell Hydraulic Fxperiments," by J. B. Francis, and is 

 for the discharge of water over a weir. This formula is 

 "Q = 3'33 ("^ " 01 "''O'''' English cubic feet, in which // 

 denotes the head of water above the sill of the weir, / its 

 length, and 11 either o or i or 2, according as the contrac- 

 tion of the vein is prevented upon both, one, or none of the 

 sides." Prof. Thomson, in the above-mentioned paper, 

 referred to this formula as identical, in its general form 

 a (/ - /3 « li)h^, with the one which he had deduced from 

 known principles as the true theoretical formula. Mr. 

 Francis put it forward merely as an empirical formula 

 which agreed with the results of his experiments, and it is 

 curious that he should have made a guess which turned 

 out to be more in accordance with the true theory, than 

 all the previous so-called theoretical formulas, which had 

 been advanced and sanctioned by the best authorities. 

 Patrick Edward Dove 



OUR BOOK SHELF 



A General Dietionary of Gcooraphy, Descriptive, Phy- 

 sical, Statistical, Historical j forming a Coniplcie Gatet- 

 \ tecr of tlic World. By A. Keith Johnston, F.R.S.E. 

 New edition, thoroughly revised. (London ; Longmans 

 and Co., 1877.) 

 The title of this work is somewhat misleading. The 

 " physical" and "historical" elements are so meagre that 

 they are scarcely worth mentioning as features of the 

 work. To call this a " complete gazetteer of the world " 

 is a misuse of the term "complete;" incomplete would 

 have been more accurate. Even on the scale of the 

 present work it would take a gazetteer at least three 

 times its size to contain anything like a register of all 

 the places one would naturally expect to find in a 

 "complete" gazetteer. The work includes a selection 

 of the more important places in the world, very few 

 towns, for example, out of the United Kingdom being 

 given, whose population is under 1,000. We find no fault 

 with the publication of a selective gazetteer, but it should 

 not pretend to be more than it is. When compared with 

 Ritter's well-known work, e.g., the proportion of places 

 found in the latter as compared with "Johnston " is some- 

 thing like five to one. We believe a service would be 

 done to the public by the issue of a gazetteer containing 

 simply all the names omitted in " Johnston." , It is not for 

 well-known places we turn up a gazetteei, but for names 

 that one seldom hears. During these Eastern troubles, 

 how many names of places not to be found in "Johnston" 

 have become of great importance, and during the war just 

 begun how many more are likely to come prominently 

 into notice ? On the other hand, much valuable space 

 is occupied with catalogues of streets and public buildings 

 in the articles devoted to well-known places like London, 

 Edinburgh, Paris, Vienna, &c. All that can be said about 

 public buildings and similar features of a town in a 

 gazetteer of this scale is practically useless ; the space 

 would be used to much better purpose by an enlarge- 

 ment of the list of names. In Russia, for example, 

 nearly all " towns " and " villages " seem to be omitted. 



many of them with thousands of inhabitants, only "dis- 

 trict towns," as a rule, being given. Poland and Finland 

 are also very unsatisfactory ; in fact these countries have 

 never been properly " gazetteered" even in Russia. 

 In several instances the "latest" information has evi- 

 dently not been obtained. To get it, indeed, would 

 involve a vast amount of research among oflicial publica- 

 tions and travellers' narratives, but in a standard work 

 such research is demanded. In Switzerland, we are in- 

 formed by a Swiss friend, much of the information is half 

 a century behind date. Under Chaux-dc-Fonds. e.:^., the 

 statement with regard to the manufacture of chains for 

 the movements of watches has not been true for at least 

 thirty years ; and there is no lace now made at St. Imier. To 

 arrange the wealth of information published by the United 

 States Survey alone would involve much time and labour ; 

 we fear that for the new edition this has not been thoroughly 

 done. Nearly two years ago Mr. W. H. Dall, of the United 

 States Coast Survey, published a Report on the moun- 

 tains in the Alaska territory. Yet no use has been made 

 of this Report though it is quite accessible. For Mount 

 St. Elias the height in the English Admiralty Chart, 14,970 

 feet is given, instead of upv/ards of ig,ooo feet, obtained by 

 the careful measurement of the United States Survey in 

 1S74. The height of Mount Fairweather is set down as 

 14,708 (1855) instead of 15,500 (1S74) ; Mount Crillon 

 13,500 instead of 15,900; Mount Cook 16,000, Mount La 

 Perouse 1 1,300, and Mount Vancouver 13,100 feet, are not 

 given. Such imperfections make one doubt if this new 

 edition has been " thoroughly revised." It is easy to give 

 information contained in census tables and in other 

 gazetteers and guidebooks, but even a work on the limited 

 scale of the present cannot be made throughout trustworthy 

 without very considerable trouble being taken. 



Zoological Classification. By F. C. Pascoe, F.L.S. 



(John Van Voorst, 1877.) 

 This small work will be found particularly serviceable to 

 many working naturalists. It is a concise compilation of 

 the sub-kingdoms, classes, and orders of the animal 

 kingdom, with lists of the famihes and most important 

 genera. Specialists will be able to find fault with some 

 of the details in many cases, nevertheless we know no 

 volume which, in the space, contains so much reliable 

 information. The larger groups are all succinctly defined, 

 with many of the most modern views incorporated ; and 

 these definitions extend to the orders. Taking the mam- 

 malia for criticism, we regret to find the Sirenia included 

 with the Cetacea, the T.Iusk Deer with the Chevrotains, 

 the Peccaries with the true Swine, and the Camels 

 between the Giraffe and the other typical ruminating 

 animals. The caecum is not " enormous " in Hyrax. 

 "Whatever gaps there may be at the present day" 

 between the Perrissodactyla and Artiodactyla "are not 

 nearly all filled in by numerous extinct forms." Such 

 errors may be found in many places ; they do not, how- 

 ever, much detract from the general value of the work, 

 which will be found more valuable as a basis for annota- 

 tion, than a book of reference. There is a very complete 

 index we are glad to say. 



Tracts relating to the Modern Higher Mathematics. 

 Tract No. 2, Trilinear Coordinates. By Rev. W. 

 Wright, Ph.D. 77 pp. (London : Messrs. C. F. Hodg- 

 son and Son, 1877.) 

 Dr. Wright is, or was until quite recently. Professor of 

 Mathematics at Wilson College, Pennsylvania. His 

 object is to make his countrymen acquainted with certain 

 branches of modern mathematics, and we learn that his 

 first venture (Tract No. 1, Determinants) has met with 

 considerable acceptance in the American universities. 

 M. Hermite, too, has expressed himself well pleased with 

 the author's standpoint, " Line grande transformation 

 s'est dcjd faite et continue encore de sc faire dans le 

 domaine de I'analyse ; des voies nouvelles plus f(fcondes, et 



