45< 



NATURE 



\_March 20, 1890 



occurring in the smaller islands. Meyer's story of the 

 whimbrels nesting on trees (probably Numenins tiro- 

 pygialis, Gould, by the way — not A", phcsopus) is quoted, 

 but without comment, and it is worthy of remark that no 

 naturalist has as yet confirmed it. Dr. Hickson is not quite 

 accurate in his statement that there are only two Celebean 

 birds which are likewise English. He must often have 

 noticed, in his rambles along shore, not only the common 

 sandpiper, but also the wide-ranging Strepstlas interpres 

 and one or more of the genus Totanus, which are not 

 unfamiliar to us at home. 



Perhaps one of the best passages in the book is that 

 describing a mangrove-swamp, where the extraordinary 

 conditions of life obtaining within its limits, and the 

 interdependence of that tree and the coral reef, are well 

 illustrated. The scenery of Talisse Island is not par- 

 ticularly beautiful, although the author does not tell us 

 so ; but that of the district of Minahassa on the main- 

 land is strikingly lovely, and he describes the view of the 

 Tondano Lake as one without an equal. It was unspoilt 

 to him even by the thought of the " heerendienst" — that 

 system of compulsory service which has acted as a red 

 rag to so many Englishmen. Dr. Hickson is not so pre- 

 judiced, and is wise enough to recognize — as did Wallace 

 — the enormous advantage which it has conferred upon 

 the people. 



" I cannot help thinking," he says (p. 208), " that every- 

 one who is really acquainted with the circumstances of 

 these colonies and the character and condition of the 

 people must admit that it is a service both necessary and 

 just. The Dutch Government has brought to the people 

 of Minahassa not only the blessings of peace and security, 

 but also the possibilities of a very considerable civiliza- 

 tion and commercial prosperity. ... In return for all 

 this, it is only just that every able-bodied man should be 

 compelled to lend a hand in maintaining this happy con- 

 dition of affairs. In a land where the necessities of life 

 are so easily obtained, ... it would be impossible for 

 the Government to obtain a sufficient number of them to 

 labour on the roads at a reasonable wage." 



The consequence is that they would be neglected. 

 The heerendienst, then, as Dr. Hickson shows, is the 

 only system possible, without overburdening the Ex- 

 chequer, or increasing the taxation beyond the endurance 

 of the people. 



We have not space to dwell upon the description of 

 the Sangir Islands, or on the mythology and customs of 

 the natives of Minahassa, which Dr. Hickson has done 

 well to put within the grasp of those who are unacquainted 

 with the Dutch language. Among the folk-lore it is 

 interesting to notice (p. 241) the story of Lumimuiit's 

 impregnation by the west wind — a story which, if we 

 mistake not, is almost identical with one of Egyptian 

 source. The " swan-maiden " tale — which, perhaps, has 

 as wide a distribution over the surface of the globe as 

 any other— again occurs in Celebes. Enough has been 

 said to show that " a naturalist in North Celebes " had 

 a varied interest in his surroundings, which he has con- 

 trived to communicate to his readers with success. A 

 little more care, perhaps, would have purged the volume 

 of several misprints, and one or two instances of involved 

 diction. 



The woodcuts with which the book is furnished are 

 well enough. We wish that anything could be said in 



favour of the "process " illustrations. That at p. 33 is 

 bad, and another at p. 137 still worse. But anything- 

 mOre muddy and meaningless than that facing p. 45 we 

 confess never to have seen. 



F. H. H. GUILLEMARD. 



SAINT- VENANT'S ELASTIC AL 

 RESEARCHES. 



The Elastical Researches of Barre de Saint-Venanf. 

 (Extract from Vol. II. of Todhunter's " History of the 

 Theory of Elasticity.") Edited, for the Syndics of the 

 University Press, by Karl Pearson, M.A., Professor of 

 Applied Mathematics, University College, London. 

 (Cambridge : At the University Press. London : C. 

 J. Clay and Sons. 1889.) 



OUR fears lest this " History of the Theory of Elasti- 

 city " should, like Thomson and Tait's " Natural 

 Philosophy," remain a magnificent mathematical torso 

 have been agreeably falsified by the early appearance of 

 this instalment of the second volume. It is devoted 

 entirely to the work of Saint-Venant, the distin guished 

 French mathematical engineer. 



Saint-Venant is one of the rare examples of a writer 

 who is equally popular with the mere mathematician and 

 with the practical engineer. To quote from the author's 

 preface to this part of the " History of Elasticity," "we 

 live in an age when the physicist awaits with not un- 

 reasonable excitement for greater revelations than even 

 those of the past two years about the ether and its 

 atomic offspring ; but we live also in an age when the 

 engineer is making huge practical experiments in elasti- 

 city, and when true theory is becoming an absolute 

 necessity for him, if his experiments are to be of prac- 

 tical as well as of theoretical value." This is the 

 opinion of the theorist ; but the engineer points to his 

 work as magnificent experiments on a gigantic scale, to 

 which he invites the theorist to an inspection, for him to 

 deduce his theoretical laws. 



So far as pure theory is concerned, the engineer trusts 

 only to Hooke's law, and Euler's theory of the beam, 

 which neglects the warping of the cross-sections. But 

 Hooke's law is shown by the testing-machine to be 

 only a working hypothesis within very narrow limits of 

 extension and compression, after which the baffling phe- 

 nomena of plasticity make their appearance, and destroy 

 all the simple mathematical harmony ; while as to Euler's 

 theory of the flexure of the beam, the editor. Prof Pear- 

 son, is at present engaged on the mathematical discussion 

 of the permissible limits of the application of the ordinary 

 theory, and, so far, the result of his investigations (in the 

 Quarterly Journal of Mathematics) is such as to strike 

 dismay in the heart of the practical man who would be 

 willing to apply his conclusions. 



The purely mathematical theory of Elasticity is, at the 

 present moment, in a very curious condition, for a subject 

 in the exact science par excellence. Not only are elasti- 

 cians divided into opposite camps of viulti-constancy and 

 rari-constancy, but we find a war of opinion raging among 

 the most recent investigators — Lord Rayleigh, Chree, 

 Love, Basset, and others. All are compelled to violate 

 apparently the most fundamental rule of mathematical 

 approximation ; and, in considering the elasticity of a 



