870 



NA TURE 



[December 30, 1922 



that "the evidence regarding the destruction of the 

 native avifauna by stoats and weasels is very incon- 

 clusive " (p. 7.;)- and in another that "these animals 

 [weasels and other vermin] are largely responsible for 

 the decrease in the numbers of native birds" (p. 89). 

 One conclusion, however, is manifest, that neither 

 in New Zealand nor elsewhere should naturalisation 

 <il exotic animals be permitted, except with the consent 

 of a properly constituted advisory committee contain- 

 ing a strong representation of biological science. 

 Perhaps we can afford to smile at the enthusiasm of 

 men who endeavoured to establish migratory buds. 

 or brought from Britain the humble-bee, Bombus 

 terrestris (now the commonest species in New Zealand), 

 to fertilise the red clover, not knowing that its trunk 

 was too short to reach the bottom of the clover flower ; 

 but we should not be subject to the vagaries of such 

 as the New Zealand legislator who, when it was pro- 

 posed to introduce half a dozen Venetian gondolas, 

 to be placed on a lake in the public gardens of Nelson, 

 protested against the extravagance and desired to 

 import only a pair, " and then let Nature take its 

 course." James Ritchie. 



Boscovich and Modern Science. 



A Theory of Natural Philosophy. Put forward and 

 explained by Roger Joseph Boscovich. Latin- 

 English edition. From the Text of the First Venetian 

 edition published under the personal superintendence 

 of the Author in 1 763. With a short Life of Boscovich. 

 Pp. xix + 470. (Chicago and London: Open Court 

 Publishing Co., 1922.) 635-. net. 



IN the time of Boscovich the line of demarcation 

 between the philosopher and the physicist or 

 mathematician was much less clearly marked than it 

 is to-day — perhaps it is better to say than it wa a Eew 

 years ago. It is therefore to be expected of a man of 

 Ecscovidis energ) and versatility living in the eight- 

 eenth century, that he should have explored the 

 borderland of philosophy and science. The book before 

 us contains the contribution of Boscovich to this 

 domain — for us the most important work of his life. 

 In it he appears to a modern as a philosopher rather 

 than a man of science, interested largely in the search 

 for and use of a priori arguments, but in close touch 

 with the scientific theories and explanations of his day. 

 Whether this classification is right or wrong, the 

 book is full of interest. Boscovich is sometimes 

 claimed as the lather of modern atomic theory, and 

 this volume provides at any rate partial justification for 

 the claim. For Boscovich shows with admirable 

 clearness how many diverse phenomena in mechanics 

 NO. 2774, VOL. I IOJ 



and even in other branches of physics can he explained 

 in a natural qualitative way on his hypothesis that 

 matter consists of discrete points accelerated towards 

 each other by a perfect definite law of suitable form. 

 But from the modern point of view his work in this 

 connexion is scarcely more interesting than the 

 earlier work of Daniel Bernoulli, or the still earlier 

 ideas of Hooke. To a mathematician perhaps the 

 most interesting sections of the book are those in 

 which Boscovich expounds the law of continuity, 

 the doctrine of impenetrability, and their consequences. 

 It is at once evident that his ideas of the properties 

 of a continuum and of a progression, though of course 

 not extensive, are invariably clear and accurate. 



Other interesting passages are those in which 

 Boscovich makes use of proofs by induction or criti- 

 cises the inductive reasoning of others — for example, 

 attempts to establish thus that matter must have 

 continuous extension. He is always careful to explain 

 why he believes his own inductive arguments to be 

 valid when he makes them. In fact one may strongly 

 suspect that his first instinct in all such cases is to 

 take up a sound sceptical point of view, with perhaps a 

 slight weakness for his own favourites. In this he is 

 by no means unique, and in full agreement with a 

 certain distinguished man of science of to-day who is 

 reported to have defined scientific truth in conversation 

 with a friend as " the theories which you and I believe, 

 and 1 include you for courtesy." 



Boscovich is firmly convinced of the underlying 

 simplicity of all natural phenomena. The main thesis 

 of his book is to show that it is conceivable that all 

 the properties of matter might be explainable on the 

 basis of his unique acceleration law. In a delightful 

 passage (pp. 105-7) he attacks the multiplicity of forces 

 used by the physicists of his day and the danger of 

 concluding that Nature is complicated when it may 

 only be that the mathematics is inadequate. 



Both as a final example of the depth and range of 

 his ideas and for its latter-day interest we must quote 

 the following passage, in which he is discussing the 

 form of his acceleration law. He has just assumed 

 that the mutual acceleration of two of his points is 

 always bounded except when the distance between 

 them actually tends to zero. He proceeds : " In this 

 case it is evident that, if a sufficiently great velocity 

 can be given to any mass, it would pass through any 

 other mass without any perturbation of its own parts, 

 or of the parts of the other. For the forces have no 

 continuous time in which to act and produce an)- finite 

 sensible motion ; since if this time is diminished 

 immensely . . . the effect of the forces is also 

 diminished immensely. We can illustrate the idea by 

 the example of an iron ball, which is required to pass 



