December 2, 1920] 



NATURE 



435 



Every Boy's Book of Geology: An Introductory 

 Guide to the Study of the Rocks, Minerals, and 

 Fossils of the British Isles. By Dr. Arthur E. 

 Trueman and W. Percival Westell. Pp. 315. 

 (London: R.T.S., n.d.) Price 6s. net. 



This is a good introduction to geology, lucidly 

 written and thoroughly up-to-date. The illustra- 

 tions are simple, and are line-sketches only, but 

 they convey their meaning. The authors rightly 

 presume that those who read their chapters are 

 prepared to be interested in the subject. There 

 is no talking round about, in the hope of disguis- 

 ing what is going to be a lesson rather than a 

 mere encouragement to learn. There is not much 

 room for originality in the selection of the facts 

 put forward ; but the merit of this book lies in its 

 accuracy and simplicity of statement. The old 

 discussions that were at one time held to be 

 necessary in every text-book, such as the evidence 

 of earth-movement afforded by coral-reefs, are 

 wisely left to larger treatises. The suggestions 

 we have to make are merely trivial. It seems 

 cumbrous nowadays to write the names of 

 chemical elements and compounds with capital 

 letters. On pp. 32 and 131 felspars and beryl are 

 respectively described as of " very complex " com- 

 position ; but, when the reader has learnt the use 

 of chemical symbols, he will not find matters so 

 alarming. On p. 33 "twinning" should be 

 omitted or more exactly defined. Potash is as 

 important in biotitc as in muscovite (p. 35). It 

 is not at all necessary for a limestone to be melted 

 before passing into crystalline marble (p. 73). We 

 are glad to note the recommendation of a bicycle 

 to the young explorer in our islands. Fossils do 

 not necessarily lie on the tracks of chars-d-bancs. 



G. A. J. C. 



Education for Self-realisation and Social Service. 

 By Frank Watts. (The New Humanist Series.) 

 I'p. xii -1-275. (London: University of London 

 Press, Ltd., 1920.) Price 7s. 6d. net. 

 L'nder the title of "The New Humanist Series," 

 with Mr. Benchara Branford as editor, the Uni- 

 versity of London Press is projecting a series of 

 volumes in which "the most modern advances of 

 knowledge will be sought in order to fructify the 

 many and varied fields of education. The subjects 

 of the curriculum will be discussed by experts not 

 too far removed by time from their own school 

 years." These will be preceded by general 

 volumes, of which the present book is the first. 

 The treatment is adequate, and may be profitably 

 compared with that of Prof. Nunn in the opening 

 volume of another educational series. Without 

 neglecting the rather intcllectualistic psychology 

 on which teachers of an earlier generation were 

 brought up, it seeks the foundations of character 

 and conduct in the innate tendencies to which the 

 child is heir from an evolutionary past. The work 

 of psycho-analysts is laid under contribution, and 

 some of their terms, such as "sublimation," arc 

 adopted or adapted. In a diagrammatic "Tree 

 of Human Development," from roots in I'dlan 

 vital, two main stems, the nutritive hormc and 

 NO. 2666, VOL. 106] 



the distributive libido, arise, and from the latter 

 are derived the flower and fruitage of the sub- 

 limated will or eros. There are many practical 

 suggestions which will be found of value by 

 teachers. 



Utilisation des Algues Marines. By Prof. Camille 

 Sauvageau. (Encyclop^die Scientifique : Biblio- 

 th^que de Botanique Appliqu<5e.) Pp. vi-(-394. 

 (Paris : Octave Doin, 1920.) Price 7.50 francs. 



Many possible uses of seaweeds are described ir 

 Prof. Sauvageau 's excellent treatise — agricultural, 

 industrial, alimentary, therapeutic. Their value 

 as manure is great, but is limited by cost of car- 

 riage. Among industrial uses of brown, algae may 

 be mentioned the kelp industries, formerly so 

 profitable as the source of soda, and still yielding 

 potash, iodine, and bromine. Algin, norgin, and 

 tangin are patented products used as dressings 

 for textiles, etc., as also are the mucilages ex- 

 tracted from red alga;. During the war acetone 

 was produced on a large scale by fermentation 

 of brown alga; in American munition factories, 

 and used as a solvent for gun-cotton, etc. By a 

 similar fermentation, alcohol can be manufactured 

 in quantity for motor fuel. The Germans devised 

 a " fuse " of Laminaria to explode shells falling 

 into water. Algae, though commonly eaten in 

 Japan, China, and elsewhere, are really valueless 

 as human food, but for domestic animals they 

 have for ages been used as winter fodder. During 

 the war French horses were successfully fed on a 

 partial diet of algae; the new food, though quite in- 

 digestible at first, gradually became assimilable, 

 probably through the adjuvant action of bacteria 

 or yeasts. Prof. Sauvageau 's monograph is a 

 welcome acquisition. 



Letters of Travel. (i892-!9i3.) By Rudyard 

 Kipling. Pp. vi + 284. (London : Macmillan 

 and Co., Ltd., 1920.) Price 7s. 6d. net. 



With his faculty for noting the little significant 

 things, as well as the big and striking things, 

 Mr. Rudyard Kipling gives us wonderful pictures 

 of life in America, Canada, and Egypt. Some of 

 the letters are old — they are reprinted from 

 periodical publications — but all are fresh in human 

 interest, because they dwell on big, essential 

 problems. The volume is Kipling at his best, 

 without the " tobacco and blood " in which he 

 often indulges, and with his wealth of illus- 

 tration and telling incidents of travel. These short 

 chapters give truer impressions of the lands they 

 treat of than all the ponderous volumes of pains- 

 taking travellers, collecting facts and arranging 

 statistics. 



.Slide Rules and How In Use Them. By T. 



Jackson. Pp. 30. (London : Chapm.in and 



Hall, Ltd.) Price is. 6d. net. 

 TnF. principles upon which the construction of 

 slide rules depend arc dcscrilicd in this pamphlet, 

 and numerous examples afe given of the methods 

 of use of such mc< h;inic;il aids In calculation. 



