144 



KNOWLEDGE. 



Apkii. 1911. 



and ghostly visions." Surely here is evidence enough, and 

 as for this one lens, all the result of direct experiment. 



Mr. Plaskitt c_ontends that if when using an oil-immersion of 

 1 -40 with the full aperture, that is. with the back lens filled 

 with white light, I then stopped it down until only three- 

 (juarters was full, I should be getting mncli nearer • 75 than 

 1 -40. an aperture not so much as a good dry quarter as to 

 resolving power. Well, that is a matter easily settled. I still 

 have the scale from which the photograph with my 

 apochromatic was taken, and shall be most happy to wait 

 upon him with it. if his home is in London. If he can then. 

 with a dry glass, produce the same appearances upon it. 1 u ill 

 concede his point. This, at least, would be a short way out 

 of the discussion. -j. -,- c;-\iitH 



THE ETKRXAL RETURN. 

 To the Editors of "Knowledge." 



Sirs, — Mr. H. D. Barcla\', in the February issue of 

 " Knowledge." raises the oft-recurring and apparently 

 insoluble question of Eternal Return, but the precise difficult\' 

 he is in is not altogether clear. 



That time and space are infinite will admit of little doubt ; 

 that the sum total of forces in the Universe is also infinite 

 is, though open to question, probably also true. The 

 fact of their being constant need not necessarily impair 

 their infinity. (Can infinity itself not be constant ?) Their 

 sum total may be constant, but their component parts are 

 subject to perpetual changing and interchanging. It is 

 this continual changing and lack of equilibrium that is of 

 the very essence of force. Pre-suppose equilibrium, and 

 our conception of force is gone. We might, indeed, say 

 that this lack of equilibrium is a permanent and essential 

 factor in the Universe. It is, as it were, the attribute of force 

 or energv itself, and, in this sense, is infinite and eternal. 



The argument, as stated by Mr. Barclay, pre-supposes this 

 permanence : — " If these forces could ever attain a position of 

 balance it would have already happened, as an infinity of 

 time has passed." Not having happened, it follows that this 

 condition of out-of-balancc is infinite, and force, therefore, is 

 also infinite. 



It is curious to note th.it Dr. Le Bon is brought in as a 

 supporter — indeed as one of the discoverers — of the eternal 

 return hypothesis, but on what ground it is difficult to 

 understand; for, in Dr. Le Bon's view, matter is constantly 

 " dis,sociating " and slowly but surely returning to the ether 

 from which it was originally derived. Once it has all returned, 

 there is an end of matter and energy alike. This is a subject I 

 happen to have alluded to in the January issue of the 

 Westminster Reviexc, and if Mr. Barclay will refer to 

 it he will see that Dr. Le Bon's teaching (if I read him 



aright I is not that of "eternal return" but of "no return." 

 It is true that here and there he lets fall a phrase which 

 betrays a doubt on the subject: but in spite of these lapses it 

 is clear that his doctrine of dissociation is closely bound 

 up with the doctrine of "no return." — matter and 

 energy are constantly being dissipated, and apparently are 

 lost for all time. It is not an inspiring doctrine, 

 and seems purely gratuitous : for there is nothing in his 

 experiments that necess.arily leads to any such inference, 

 while the operations of Nature in general point altogether the 

 other way. Nothing is clearer than that Nature, within the 

 bounds of our experience, works, both on a large and on a 

 small scale, in cycles of some sort. Almost all her operations 

 are rhythmic. There is a constant ebb and flow : an evolution 

 and a devolution. If this is the case in regard to phenomen.a 

 within our limited experience, is it not a reasonable inference 

 that this evolution and de\olution extends far outside our 

 experience and beyond our conception ? — that it is, in fact, 

 infinite and universal. 



The following quotations fr(.)ui Dr. Le Bon's "The Evolution 

 of Matter" (Book VI. Chapter VIII. I sufficiently indicate his 

 \ lews on the subject : — " We now know that matter vanishes 

 slowly, and consequently is not destined to last for ever." . . . 

 " What is the fate of the atom of electricity after the dis- 

 sociation of matter ? Is it eternal while matter is not ? " 

 . . . . " Once it [the electric atom] has radiated away 

 all its energy, it vanishes into the ether and is no more." 



. . . " This last, therefore, represents the final nirvana 

 to which all things return after a more or less ephemeral 

 existence." 



One saving clause (in the same chapter) is as follows : — 

 ■' Nothing leads to the belief that they [i.e., things in general] 

 had a real beginning or that they can have an end." 



Thus we see that Dr. Le Bon's teaching is unmistakably in 

 the direction of the final destruction of matter and energy, 

 although the last quotation I have given betrays something of 

 an open mind on the subject, — a subconscious admission though 

 it possibly may be. 



.As often as we recur to this problem we are inevitably met 

 with this consideration : that, from the nature of the case, the 

 finite cannot grasp the infinite ; and whatever our speculations 

 may be, we must, of necessity, always labour under this 

 disability. .As Wallace has said : " Of infinity, in any of its 

 aspects, we can really know nothing, but that it exists and is 

 inconceivable." 



This, however, is no reason for withholding our speculations, 

 so long as they have a substantial basis of fact ; for it is only 

 by pressing them forward that we can ever hope to in any 

 degree qualify our present limitations. ... ,- rTcu-viiv 



NOTICI'.S. 



THE ZOOLOGICAL SOCIETY, ADDITIONS TO THE 

 MEN.AGERIE. — Daring the month of February no less than 

 one hundred and twenty-three additions to the Zoological 

 Society's menagerie were registered. Among them are the 

 following animals which are new to the collection: — .A Dwarf 

 Mongoose ( Helogale varia), from Mombasa, presented by 

 the Rev. W. Douglas Braginton, on Feb. 27th ; a Black-footed 

 Polecat (Putoriiis iiigripes), from North America, received in 

 exchange on Mar. 16th; two Dybowski's Deer (Cervns 

 hortiiloriiiu ), from Manchuria, presented by Sir Edmund 

 Loder, Bart., F.Z.S., on Feb. 23rd; and an .Aldunati's Finch 

 (Phrygiliis aldnnatiil, from Chili, presented by Miss Phillis 

 True, on Feb. lith. 



ROYAL INSTITUTION.— The following are the Lecture 

 .Arrangements at the Royal Institution after Easter: — 

 Mr. J. E. C. Bodley, Three Lectures on (1) Cardinal Manning; 

 (2) The Decay of Idealism in France, and of Tradition in 

 England; (3) "The Institute of France; Professor Frederick W. 

 Mott, Two Lectures on the Brain and the Hand; Professor 

 W. W. Watts, Two Lectures on (1) The Ancient Volcano of 

 Charnwood Forest (Leicestershire); (2) Charnwood Forest 

 and its Fossil Landscape ; Professor R. W. Wood, of the 



Johns Hopkins University, Three Lectures on the Optical 

 Properties of Metallic Vapours (Illustrated) ; Dr. W. N. Shaw, 

 Two Lectures on .Air and the Flying Machine: (1) The 

 Structure of the Atmosphere and the Texture of .Air Currents ; 

 (2) Conditions of Safety for Floaters and Fliers; Mr. T. 

 Tliorne-Baker, Two Lectures on (1) Changes effected by 

 Light ; (2) Practical Progress in Wireless Telegraphy 

 (Illustrated) ; Professor Selwyn Image, Three Lectures on 

 (1) John Ruskin; or. the Seer and Art; (2) William Morris; 

 or. the Craftsman and Art ; (3) Walter Pater ; or, the 

 Connoisseur and .Art; Mr. W. P. Pycraft, Two Lectures 

 on Phases of Bird Life: (1) Flight; (2) Migration; and 

 Mr. W. L. Courtney, Two Lectures on Types of Greek 

 Women ; Xausicaa and the Homeric Women ; Sappho and 

 the Aeolian Poets ; .Aspasia and Pericles. The Friday 

 Evening Meetings will be resumed on April 2Sth, when a 

 Discourse will be given by Professor W. M. Flinders Petrie 

 on The Revolutions of Civilization. Succeeding Discourses 

 will probably be given by Professor Martin O. Foster, 

 Professor William Stirling, Professor R. W. Wood, Professor 

 Gilbert Murray, Commendatore G. Marconi, Professor Svante 

 .Arrhenius. and other gentlemen. 



