

May 21, 1903] 



NA TURE 



53 



and greater prominence given to habits. So far, how- 

 ever, as we can see, the author appears to have re- 

 corded little or nothing new in regard to the latter,- 

 and we venture to think that he has missed an oppor- 

 tunity of giving fuller detail as to adaptation to en- 

 vironment, especially as regards coloration. Neither 

 is he to be congratulated as regards his style in many 

 parts of the work, as witness the following sentences 

 in the description of the bearded tit (p. 184) :— " The 

 family characters are the same as the generic ones. 

 It is found in various parts of Europe and Asia." It 

 may be also pointed out that " Obb " (p. 261) is not 

 the name of a well-known Siberian river. Again, the 

 introduction of the word " Raptores " in connection 

 with a cut on p. 84 is unnecessary and puzzling, when 

 it is not, so far as we can see, used in the text. And 

 this reminds us that a glossary of eight items seems 

 strangely inadequate in a work where a considerable 

 number of technical terms are necessarily employed, 

 for we quite fail to see why it is necessary to explain 

 the meaning of " aftershaft ' and leave the reader to 

 find out the signification of " primary." 



As regards the illustrations, we have nothing but 

 ( i.nimendation to bestow, the full-page plates by Mr. 

 W hymper — and especially the one of kingfishers — 

 being exquisite delineations of bird-life. We notice, 

 however, that the small text-figures of birds' heads are 

 for the most part the well-known cuts of Swainson, 

 which were used with full acknowledgment by Prof. 

 Newton in his " Dictionary of Birds." Why, we may 

 ask, has the author thought fit to depart from this, 

 excellent practice, and to publish the cuts in question 

 as though they were original ? R. L. ; 



Thf Bermuda Islands. By A. E. Verrill, Yale 

 L'niversity. (Published by the Author, New Haven, 

 ("onn., U.S.A., 1902.) 

 1 \ this book, reprinted from the Transactions of the 

 C onnecticut Academy of Sciences, Prof. Verrill gives 

 an account of the Bermuda group which is intended 

 to subserve four distinct purposes ; first, that of a 

 general guide-book on the history, structure, and pro- 

 ductions of the islands, for the use of visitors ; second, 

 Q- an introductory text-book to the study of the natural 

 history of the archipelago ; third, of a record of the 

 more important changes in the flora and fauna already 

 caused by man ; and, lastly, that of a general intro- 

 duction to a series of more technical memoirs, by the 

 author and other naturalists, on the natural history and 

 geology of the islands, now in course of publica-i 

 tion. The present volume includes a general descrip-' 

 tion of the islands, an account of their physical geo- 

 graphy and meteorology, a sketch of their discovery and 

 early history, and an account of the animals and plants 

 introduced or exterminated since their discovery by 

 the Spaniards about 1510. The last part of Prof. Verrill's 

 work is of special value, for, so far as appears, no 

 huinan being had set foot on the islands before that 

 date. Accounts of the geology and marine zoology 

 of the group are promised in a later volume. The 

 l)(H)k is illustrated by thirty-eight excellent plates, and 

 a large number of cuts, and a valuable bibliography 

 is appended. 



/.a Pratique des Fermentations industrielles. By E. 

 Ozard. Pp. 168. (Paris : Gauthier-Villars, n.d.) 

 Price 2.50 francs. 



This book is intended specially for the use of brewing 

 ( hcinists. The author gives the essential principles 

 underlying the various fermentation processes, which 

 allow of the transition of sugars and starches into 

 alcoholic products, and also broadly indicates how 

 those processes are carried out in practice. 



NO. 1 75 I, VOL. 68] 



LETTERS TO THE EDITOR. 



[The Editor docs 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 part of Nature. 

 No notice is taken of anonymous communications.] 



Psychophysical Interaction. 



A BRIEF note to remove a possible misunderstanding sug- 

 gested by Prof. Minchin. He seems to think, or to imagine 

 that others will think, that when speaking of the action of 

 mind on matter I conceive of mind as a thing that can 

 sustain a "reaction"; so that a stress might exist with 

 matter at one end and mind at the other. Such an absurdity 

 would indeed play havoc with the laws of mechanics ; at 

 any rate, I never entertained such a notion for a moment, 

 whether for a guiding or for any other kind of force. If 

 I lift a table it is quite certain that the weight of the 

 table, plus its mass-acceleration, is transmitted through my 

 boots to the floor : so far mechanics is supreme. But not 

 even Prof. Minchin could calculate whether I shall lift the 

 table or not, nor what I shall do with it when I have lifted 

 it. I should obey every law of mechanics if I cast it on a 

 bonfire ; but I should have interfered with the course of 

 nature, regarded as a mechanically determinate problem, 

 even by only lifting it. 



I want to understand the nature of this interference better ; 

 I have no other " anxiety " on the subject. 



Incidentally I should like to transfer to your pages a 

 most interesting and clearly-worded claim made by Sir 

 W. T. Thiselton-Dyer in to-day's Times : — 



"Directive power ... wipes out [meaning would wipe 

 out if it were established] . . . the whole position won for 

 us by Darwin. It is no use mincing matters. Students of 

 the Darwinian theory must be permitted to know the 

 strength and weakness of their dialectic position. What 

 that theory did was to complete a mechanical theory of the 

 Universe by including in it the organic world." It is the 

 last sentence to which I would direct attention. 



Athenaeum Club, May 15. Oliver Lodge. 



I AM not clear that it is wise to endeavour to aid Sir 

 Oliver Lodge out of the pit he has, it seems to me, quite 

 unnecessarily fallen into. But I will put a rope down to 

 him, as it must be very uncomfortable down at the bottom. 



.•\lmost every mechanical problem leads by the application 

 of ultimate mechanical principles to a differential equation. 

 The solution of this equation involves a certain number of 

 constants which may be infinitely many, but which we 

 always find to be absolutely determined by the initial con- 

 ditions. At first sight it seems difliicult, without tacitly 

 dropping a fundamental mechanical principle — such as that 

 of momentum — to allow for " guidance " and " freewill " 

 therein. But differential equations occasionally admit of 

 singular solutions. We may follow up a particular solution, 

 absolutely defined by the initial conditions, until we run 

 onto the singular solution. After this we can stick to 

 the singular solution or leave it again at any other contact 

 with a particular solution, which will still satisfy the funda- 

 mental differential equation. Can " guidance " and free- 

 will correspond to a shunt of this kind? 



I am quite unaware of any differential equation in 

 mechanics providing a good illustration of this suggestion. 

 Still, we must get Sir Oliver up to the surface again, and 

 this is the only rope by which I can conceive him 

 ascending. k.A.-k.v. 



" Red Rain" and the Dust Storm of Februaiy 22. 



The Marquess Camden recently sent me a sample of fine 

 sand or dust collected from the roof of Bayham Abbey, 

 Lamberhiirst, shortly after the great dust storm of February 

 22, which I have caused to be examined. As the results 

 appear to be of interest, especially in reference to Mr. 

 Clayton's contribution to the Proceedings of the Chemical 



