May 13, 1920] 



NATURE 



323 



enthusiasm and by his introduction to the fascinat- 

 ing work of Fabre. 



The author shows us Arcachon, not as a 

 modern creation on a promontory in a featureless 

 Jagoon, but as the product of great natural forces, 

 conspiring for the health of man. The winds 

 blow over it fraught with warmth from tropic 

 waters; the sands are kept from wandering by 

 the growth of aromatic pines ; and the subsoils 

 that can be traced southward across the vast 

 Pliocene estuary of the Landes represent for the 

 naturalist the spoils of the Central Plateau and 

 the Pyrenees. Like Prof. Tornquist in East 

 Prussia (Nature, vol. Ixxxv., p. 468), but with a 

 little more professional formality, Dr. Lalesque 

 has conquered in a field that offered little promise 

 to the unobservant eye. G. A. J. C. 



Our Bookshelf. 



Iron Bacteria. By Dr. David Ellis. Pp. xix + 

 179 + V plates. (London: Methuen and Co., 

 Ltd., 1919.) Price 105. 6d. net. 

 Ix this book Dr. David Ellis has compiled a 

 monograph on a subject which he has largely 

 made his own, and on which he can speak with 

 first-hand knowledge. The group of micro- 

 organisms discussed is important, and one 

 of the makers of geological history, for many 

 of the bog iron ores owe their formation largely 

 to the activities of iron bacteria, and other iron 

 ores may be due to the same cause. In modern 

 life these organisms are of importance to the 

 water engineer in relation to water reservoirs, 

 the corrosion of conduit pipes, and the general 

 appearance and clarity of water supplies. 



The iron bacteria are a heterogeneous group 

 of organisms, scarcely bacteria in the strict sense, 

 belonging to several genera — -Leptothrix, Clado- 

 thrix, Crenothrix, and others. The iron is col- 

 lected from the water in which they live, and 

 stored in a concentrated state as ferric hydroxide 

 in the mucilaginous sheaths which surround their 

 bodies. The ferruginous deposit in the membrane 

 is often so great that it exceeds the volume of 

 the organism itself, and the iron-impregnated 

 membrane may persist for long after the dissolu- 

 tion of the organism. 



Some of these organisms may occasionally 

 multiply in a very short time to such an extent 

 as in the course of a few weeks to change entirely 

 the character of the water in which they are 

 present, as was the case at Cheltenham in 1896. 

 They may also cause encrustations in the pipes, 

 and the group is therefore of considerable 

 economic importance. Six species are fully 

 described, and methods of treatment to retard 

 their activities in water supplies are detailed. The 

 book is well produced and illustrated, and forms 

 a standard work on the subject. 



R. T. H. 

 NO. 2637, VOL. 105] 



Meteorology for All: Being some Weather Prob- 

 lems Explained. By Donald W. Horner. With 

 an Introduction by M. de Carle S. Salter. 

 Pp. xvi-h 184 4- vii plates. (London: VVitherby 

 and Co., 19 19.) Price 65. net. 

 The science of the weather may well make a 

 wider appeal than any other branch of science, 

 and the opening for a book which is not only 

 scientifically accurate, but also simple and easily 

 comprehended, is therefore very great. The 

 author of the present work has realised that the 

 opening exists, and has endeavoured to fill it, but 

 his attempt can scarcely be considered successful. 

 A few quotations will illustrate the nature of the 

 book. In estimating cloud amounts on the scale 

 o-io we are told that "if there is one cloud upon 

 the horizon or in any part of the sky we put i." 

 For obtaining true bearings from a compass, "the 

 magnetic variation in the British Isles is now 

 14° W." Again: "There is no more sure pre- 

 cursor of a gale than the ' wind-dog,' or coloured 

 parhelion " (p. 2), which may possess some degree 

 of truth, but scarcely seems compatible with : 

 " When these halos are coloured and accompanied 

 by parhelia or mock suns, they generally precede 

 very dry weather" (p. no). Even in such a 

 simple matter as giving the equivalent velocities 

 of the Beaufort numbers, the author falls into 

 error. Some chapters are better than others, but 

 the book can certainly not be recommended as a 

 safe guide to put into the hands of the non-techni- 

 cal reader without previous knowledge of meteor- 

 ology. J. S. D. 



The Psychology of the Future. {" L'Avenir des 

 Sciences Psychiques.") By Emile Boirac. 

 Translated and edited with an introduction by 

 W. de Kerlor. Pp. xiii + 322. (London: 

 Kegan Paul, Trench, Trubner, and Co., Ltd., 

 n.d.) Price 105. 6d. net. 

 The author deals with the more debatable classes 

 of psychical phenomena discussed at the Paris 

 Congresses of Experimental Psychology of 191 1 

 and 1913, and defined as "the phenomena which, 

 produced in animate beings or as an effect of their 

 action, do not seem to be entirely explicable by 

 the laws and forces of nature already known." 

 They are classified as : Hypnoidal, including dis- 

 sociation of personality and " cryptopsychism " 

 (subconscious action) ; magnetoidal, which are sup- 

 posed to comprise mesmerism, telepathy, and 

 "hyloscopic" phenomena (unexplained actions of 

 inanimate objects on animate beings) ; and spirit- 

 oidal, which imply agents of a psychological 

 nature more or less analogous to human intelli- 

 gence. The author proposes the term "bi- 

 actinism " (bio-actinism?) for any phenomena in 

 which a radiating influence is apparently exerted 

 at a distance over other animate beings. For 

 "clairvoyance," or knowledge obtained by certain 

 individuals apparently independently of the 

 normal senses, he prefers the term "meta- 

 gnomy." On the question of the spiritistic hypo- 

 thesis the author maintains a non-committal atti- 

 tude. 



