August 3, 1905] 



NA TURE 



317 



lakes, important enough to prevent the observer from 

 seeing low objects situated on the opposite shore. 



Some preliminary remarks deal with general con- 

 siderations on pressure, density, and compressibility 

 of the water. The mechanical part includes the study 

 of the different movements to be observed in lakes, 

 viz. progressive waves, such as are known to every- 

 body, stationary waves or " seiches," and currents. 

 " Seiches " were first rationally studied by Prof. Forel 

 in the Lake of Geneva, and have been found to e.xist 

 in many other lakes; they are, for instance, now 

 being investigated in the lochs of Scotland by the 

 Lake Survey. Being waves as long as the lake, they 

 cause periodical rising and falling of the water-level, 

 though these tides are very often inconspicuous, and 

 only to be recorded by limnimeters or registering 

 apparatus ; they v-ary from some millimetres up to 

 1.87m. (highest " seiche " in the Lake of Geneva), 

 and much more in the great lakes of America. This 

 special kind of wave, which affects the whole body of 

 the lake, is probably due to several factors acting 

 together or separately, such as sudden variation of 

 atmospheric pressure, changes in the strength or 

 direction of the wind, &c. Older explanations, as 

 lunar attraction or earthquakes, have been shown to 

 be untenable as general causes of " seiches." 



The acoustic properties of lakes are dealt with in 

 a short chapter. The most attractive feature of any 

 lake is its colour, its greater or less transparency, 

 its reflection of the surroundings, and other optical 

 phenomena, such as refraction in or above the water. 

 The explanation, however, of all these facts, which 

 anybody may observe and enjoy, is often difficult and 

 intricate even to men of science. The author of the 

 present work has the merit of dealing with this 

 optical chapter in a very intelligible and attractive 

 way, giving briefiv the most accredited theories of 

 the phenomena treated of. 



The last chapter deals with the thermic properties 

 of lakes, such as distribution of temperature, seasonal 

 changes, formation of ice, and storage of the 

 summer's heat by the water. 



A bibliographical list of the most recent and im- 

 portant works on physical limnology concludes the 

 book, and makes of it a very useful guide and an 

 excellent risunx^ of the actual state of our knowledge 

 of this subject. 



A Catalogue of North American Dipfcra or Two- 

 7vinged Flies. By J. M. .Mdrich. (Smithsonian 

 Miscellaneous Collections, part of vol. xlvi.) Pp. 

 680. (City of Washington, 1905.) 

 The second edition of Osten-Sacken's " Catalogue of 

 North American Diptera " was published in 1878, and 

 an enormous amount of work in the order has natur- 

 ally been accomplished since. Prof. .Mdrich's catalogue 

 takes in the whole of North America, from Panam.n 

 on the south to Greenland and the Aleutian Islands 

 on the north ; and also the whole of the West Indies, 

 even down to Trinidad, adjoining Venezuela. " There 

 is no place to draw a line between the islands. The 

 Bermudas and the Hawaiian Islands are not in- 

 cluded." 



According to our own knowledge of other orders, 

 we cannot quite agree with Prof. Aldrich. The fauna 

 of Trinidad appears to us to have no relation to that 

 of the islands further north, and to be purely South 

 American, while the Bermudas clearly belong to North 

 America. On the other hand, that of the Hawaiian 

 Islands (apart from introduced species) is one of the 

 most insular in the world; and, in this respect, may be 

 compared with that of New Zealand, though far less 

 conspicuous or extensive. 



Prof. Aldrich has not numbered or mentioned the 

 NO. 1866, VOL. 72] 



number of species admitted in his catalogue (which 

 is brought down to January i, 1904); but we may 

 say that the introduction occupies 4 pages, the 

 system of classification i, the bibliography (with ad- 

 ditions) 77, the index of (59) families 1, and the 

 index of genera 12. The catalogue itself occupies 

 5.S2 broad pages, and the distribution and synonymy 

 appear to be very fully given. To criticise such a 

 work in detail would only be possible for a specialist 

 in Diptera, and in any case would occupy much more 

 space than we could give to it; and we have, there- 

 fore, confined ourselves to observations on its scope 

 and contents. 



Elementary Experimental Science. An Introduction 

 to the Study of Scientific Method. By W. May- 

 howe Heller, B.Sc, and Edwin G. Ingold. Pp. 

 220. (London : Blackie and Son, Ltd., 1905.) 

 Price 2S. 6d. net. 

 The course of work in elementary science presented 

 by the authors of this little book is modelled upon 

 the plan which, it is satisfactory to know, is adopted 

 in all good modern secondary schools. The con- 

 sequence is that there is little which is new in the 

 volume, though the methods of presenting familiar 

 experiments and of setting forth practical instructions 

 for laboratory exercises supply abundant evidence of 

 the experience and teaching ability of the authors. 



The book is quite suitable for the use of young 

 pupils except for the paragraphs containing hints to 

 teachers which are scattered up and down the 

 chapters. It is unwise to lead children to suppose 

 their teachers to be in need of instruction, and it may 

 be asked, " May it not be supposed that most teachers 

 have acquainted themselves nowadays with the aims 

 and methods of elementary science instruction? " In 

 any case, the teacher should not be addressed directly 

 in the book intended for the use of his pupils. 



The book is interesting since it shows that in the 

 opinion of some at least of the most enthusiastic 

 advocates of " heuristic " methods of instruction there 

 is a good purpose served by a well-arranged text-book 

 in introducing children to the study of scientific 

 method. Teachers looking for a book containing 

 a sensible, practical course of work in science should 

 examine this one with care. 



Astronomischer Jalireshericlit. By Walter F. Wisli- 

 cenus. Vol. vi., containing the literature of the 

 year 1904. Pp. xxxviiH-6i2. (Berlin : Georg 

 Reimer, 1905.) Price 19 marks. 



This is the sixth year of the issue of this very 

 valuable publication, and it possesses all the vitality 

 of the former volumes. It was thought by the re- 

 viewer of the previous year-books that the publication 

 of the branch E, astronomy, an annual issue of the 

 International Catalogue of Scientific Literature, 

 would take the place of the present compilation, since 

 they both for the most part cover the same ground. 

 This, however, seems not to be the case, and perhaps 

 the reason lies in the fact that the volume before us 

 gives in many cases a brief risumi of the contents 

 of the book or publication to which reference is 

 made. 



The present volume contains 2280 references, and 

 as these with their brief summary of contents cover 

 595 pages, and an excellent " name " index which 

 follows is responsible for another 17 pages, the matter 

 contained therein is considerable. 



The high standard maintained throughout reflects 

 the greatest credit on the compiler and his seven 

 co-workers, and renders the volume a necessary and 

 valuable addition to every astronomical library and 

 observaton,'. ' W. J. S. L. 



