148 



NA TURE 



[June 15, 1905 



explanation. It has been suggested that the radio- 

 active emanation which is always present in the 

 atmosphere in varying quantities may not be without 

 influence on the human organism, and if. .ns Elster 

 and Geitel suppose, this emanation is mainly derived 

 fiom the underground air, which is more copiously 

 discharged into the atmosphere as pressure decreases, 

 it may be possible to establish a connection between 

 the " storm feel " and the presence of radio-active 

 emanation. If this be so we should expect to find the 

 effect more pronounced with a falling than with a 

 rising barometer, and, in the absence of direct measure- 

 ments of the amount of emanation, the results obtained 

 from a classification of the days, or perhaps better still, 

 by a subdivision of the data used in constructing the 

 present curves, on this principle would probably be in- 

 teresting. Such a separation might prove profitable 

 from a purely meteorological point of view, apart from 

 all considerations of emanations, radio-active or other- 

 wise. Possibly the peculiar abnormalities shown by 

 most of the data for days of calm may be to some 

 extent due to similar causes. The connection is, how- 

 ever, a very complicated one ; attempts to trace a 

 similarity between days of calm and days of low 

 barometer fail signally. 



We cannot here enter into a discussion of all the 

 results or criticise the individual conclusions arrived 

 at. In the final chapter Dr. Dexter further develops 

 his thesis of the " available energv " and " emotional 

 state " in the light of all the accumulated evidence, 

 and conies to the conclusion that the effect of weather 

 changes is greater on the former than on the latter, at 

 any rate in its practical effects on conduct. 



The study of the problems dealt with in the book is 

 not without a certain practical interest to all who 

 are responsible for the control of large numbers of 

 individuals. If certain meteorological conditions can 

 be shown to have a deleterious or beneficent influence 

 on conduct or working capacity, it is well that we 

 should recognise the fact as clearly as possible, and 

 do what we can to mitigate the harmful conditions. 

 Man cannot hope to control the weather, but he can 

 modify the highly artifici.il conditions under which he 

 lives to a very large extent. 



.4 UMXOLOGICAf. MONOGRAPH. 

 Le Leman, Monographic Limnologique. By Prof. 



F. A. Forel. Vol. iii. Part ii. Pp. 410-715. 



(Lausanne: F. Rouge et Cie., 1904.) 

 T N the issue of this, the second part of his third 

 i volume. Prof. Forel completes his great mono- 

 graphic study of the Lake of Geneva. The veteran 

 pioneer of scientific limnological research is to be con- 

 gratulated on the successful termination of his monu- 

 mental task, commenced some half-century ago. 



The impetus which the study of lakes lias received 

 from the labours of Forel has now carried us so far 

 that we find it diflicult to realise the arduous nature 

 of the work accomplished by him, who had in so 

 many different directions to make the first tentative 

 trials of methods of research with which all students 

 of limnology are now familiar. The completed work 

 is not merely a compendious study of the Lake of 

 NO. 1859, VOL. 72] 



Geneva, but is besides of the utmost value as a 

 general study of the nature of fresh-water lakes. In 

 his painstaking study of this one lake he has been so 

 fortunate as to observe and explain in a satisfactorv 

 manner many phenomena of general scientific interest 

 and importance, among others the mysterious rise and 

 fall of the waters of the lakes now known as seiches, 

 the peculiar abyssal fauna of the lake, S:c. 



The present part of the work, which is mainly 

 historical, deals with such varied subjects that it is 

 difficult to particularise. Nothing having the slightest 

 connection, direct or indirect, with the Lake of Geneva 

 is destitute of interest for Prof. Forel, and we find 

 here discussed many questions which a less enthu- 

 siastic limnologist might have been content to leave 

 to students of other departments of knowledge. He 

 gives a riswni of the history of the surrounding 

 countries, of legislation, the fluctuations of population, 

 local traditions, &:c. More particularly apposite to 

 the subject are the history of the lake dwellings, 

 undertaken fifty years ago, in companv with a band 

 of archaeologists of which he laments that he is the 

 only survivor, the history of navigation, of fishing, 

 and of pisciculture. 



The history of navigation is treated very fully, from 

 the canoe of the lake dweller to the modern steamer, 

 and is illustrated with reproductions of many ancient 

 pictures of ships; with such fulness of detail is the 

 subject treated that we have a list of steamers plying 

 on the lake from the GuiUaume-TeU of 1S23 to those 

 of the present day. 



The ancient tradition of the " eboulement du 

 Lauredunum " is discussed in its scientific bearings. 

 The tradition, supported by contemporary chronicles, 

 is that in the year 563 .x.D. a mountain was precipi- 

 tated into the lake, destroying a castle, villages and 

 churches, causing a flooding of the shores of the 

 lake, and much destruction of property and life in 

 Geneva. He shows that a landslip, such as has 

 occurred several times in history, could not account 

 for the production of great floods. Although he has 

 abandoned the belief that earth movements habituallv 

 produce seiches, he admits that a great earthquake 

 might be the cause of the land-slide, and coincidently 

 of a great seiche, which would cause destruction on 

 the shores of the lake. He thinks it more probable, 

 however, that at a time of ordinary flood, when the 

 waters of the lake were very high, an ordinarv seiche 

 of no more than a metre of amplitude might cause 

 considerable flooding in Geneva, and perhaps wash 

 away some wooden bridges and houses, the connec- 

 tion with the landslip being a mere coincidence. 



In his philosophical reflections at the conclusion of 

 his work. Prof. Forel claims that there have been few 

 problems presented to him in the course of his in- 

 vestigations which he has not been able to solve, and 

 the more difficult of these few are general problems, 

 not belonging to his special province, and the solu- 

 tion of which must be sought in other lakes. He 

 would, however, guard against this assertion being 

 misunderstood as a boastfully complacent assumption 

 that he has exhausted' the subject. Everv naturalist 

 has his limits, determined from within by the extent 

 of his powers, from without by the state of the 



