88 



NATURE 



[Septembkr 24, 1 9 14 



Kinship and Social Organisation. By Dr. 

 W. ri, R. Rivers. Pp. v + 96. (London: Con- 

 stable and Co., Ltd., 1914.) Price zs. 6d. net. 

 Dr. Rivers has made a speciality of the adapta- 

 tion of the genealogical method to the interpreta- 

 tion of social facts, to which he has devoted much 

 knowledge and hard thinking. In the present 

 collection of lectures delivered at the London 

 School of Economics he uses his special studies of 

 social life in Melanesia to a consideration of the 

 classificatory system, the essential feature of 

 which is the application of its terms, not to single 

 individual persons, but to classes of relatives which 

 may often be very large. The discovery of this 

 system was the work of Lewis Morgan, who, 

 diverting his attention from the facts at his dis- 

 posal, attempted to formulate a condition of 

 general promiscuity developing into group 

 marriage, a view offensive to his readers and cer- 

 tain to meet with active criticism. His first 

 opponent was J. F. McLennan, who urged that 

 the terms used formed merely a code of courtesies 

 and forms of ceremonial address for social inter- 

 course. Another theory, that of Prof. Kroeber, 

 suggested that the use of these forms does not 

 depend upon social causes, but that they were 

 conditioned by causes purely linguistic and psy- 

 chological. 



Dr. Rivers, after a careful analysis of the facts, 

 has little difficulty in disposing of these theories. 

 He shows that the process of determination of the 

 nomenclature of relati-^nship by social conditions 

 has been rigorous and exact ; further, that every 

 detail of these systems has been so determined. 

 " Even so small and apparently insignificant a 

 feature as the classing of the sister-in-law with the 

 sister has been found to lead back to a definite 

 social condition arising out of the regulation of 

 marriage and of sexual relations." The lectures 

 form a useful contribution to the study of the 

 history of human marriage. 



The Farm Woodlot: a Handbook of Forestry for 

 the Farmer and the Student in Agriculture. By 

 E. G. Cheyney and Prof. J. P. Wentling. Pp. 

 xii + 343. (New York: The Macmillan Co.; 

 London: Macmillan and Co., Ltd., 1914.) Price 

 6s. 6d. net. 

 This is an excellent handbook of elementary 

 forestry, specially adapted for the use of farmers 

 and students of agriculture in North America, yet 

 containing much that should be of interest to 

 landowners in this country. There are well- 

 written chapters on practical sylviculture, on forest 

 mensuration, protection and utilisation, on orna- 

 mental planting, and about the durability and pre- 

 servation of timber. A special article deals with 

 the economic position of the forest and the work 

 of afforestation in the modern State. The authors 

 discuss the question of the apportionment of the 

 soil of a country into the two classes of agricul- 

 tural and forest lands, on the only just basis; a 

 comparison of the net revenues obtainable from 

 the land under other crops, and under trees. 

 Most of us, who regard the United States as pro- 

 ducing timber only from her virgin forests, will 

 NO. 2343, VOL. 94I 



learn with surprise that already in New England 

 plantations of white pine have yielded six per 

 cent, annually on the investment. 



Another chapter is devoted to the history of the 

 forests of Germany, the United States, and 

 Canada. It is satisfactory to hear that although 

 the progress of scientific forestry in Canada has 

 been slow, and dotted with many set-backs, the 

 prospect at present is promising. In the United 

 States the Forest Service has long been at work, 

 and is now carrying out on the extensive territory 

 under its jurisdiction a magnificent programme, in 

 which the question of profit is never forgotten, all 

 its measures being governed by business prin- 

 ciples, none of them by sentiment. 



Matriculation Mechanics. By Dr. William Briggs 

 and Prof. G. H. Bryan. Third edition. Pp. 

 viii + 363. (London: W. B. Clive, University 

 Tutorial Press, Ltd., 1914.) Price 35. 6d. 

 Advantage has been taken of the publication of a 

 new edition of this well-known class book to add 

 a collection of simple experiments to illustrate the 

 fundamental principles of mechanics. This addi- 

 tion will certainly increase the usefulness of the 

 book. 



LETTERS TO THE EDITOR. 

 [The Editor does not hold himself responsible for 

 opinions expressed by his correspondents. Neither 

 can he undertake to return, or to correspond with 

 the writers of, rejected manuscripts intended for 

 this or any other pnrt of Nature. No notice is 

 take)i of anonymous Lutnmunicalions.^ 



Renunciation of Honorary Degrees. 



I HAPPEN to see in one of the Dutch journals that 

 a number of German men of science have divested 

 themselves of honours bestowed upon them by British 

 universities and learned societies, on account of the war 

 between England and Germany. 



Will you allow me to express the hope, by means 

 of this letter, that my British friends will not recipro- 

 cate this action by a similar one ? 



To my mind, worse than the young lives sacrificed, 

 worse than the destruction of ancient monuments of 

 arts and science, is the almost inevitable consequence 

 of this terrible wai- : the sowing of hatred and distrust 

 between different nations. 



Now it is my firm belief that it is the duty and the 

 privilege of scientific men all the world over to do 

 all in their power gradually to allay these feelings of 

 hatred and distrust. 



For this reason especially I regret greatly the action 

 of the German "savants," and earnestly pray my 

 British friends to abstain from similar action. 



J. P. LOTSY. 



Perpetual Secretary of the Dutch Society of 

 Sciences, Haarlem, September 12. 



The Green Flash. 



As the green flash continues to appear in your 

 columns, may I give some limitinir observations. At 

 sea I have always seen it, ii the horizon is clear and 

 not too red. It is also well seen over distant moun- 

 tains in Egypt at rising, when the sky is less red 

 than at setting. The horizon may be as near as two 

 miles, and still show traces of a green edge. At any 

 distance less than live miles the disappearance can be 

 followed up for some seconds by walkinji;^ up a slope, 

 so as to keep the green edge under continuous ob- 

 servation. W. M. Flinders Petrie. 



