September 22, 1898] 



NATURE 



495 



that a more moderate price will place it within the 

 means of many students who at present will certainly 

 be debarred from possessing it, save through the 

 intermediation of the second-hand bookseller. 



Automobiles sur Rails. By G. Dumont. Pp. 184. 



(Paris : Gauthier-Villars et Fils. Masson et C'«.) 

 Rdgularisation du Mouvement dans les Machines. By 



L. Lecornu. Pp. 217. (Paris: Gauthier-Villars et 



Fils. Masson et C*^) 



These two volumes belong to the Encyclopedie scien- 

 tifique des Aide-Memoire, and, like most of the volumes 

 in this series, they contain concise statements of the 

 subjects with which they deal. M. Dumont examines 

 the various systems of horseless traction in use. He 

 begins with steam motors, and then in successive short 

 chapters describes compressed air motors, gas and oil 

 motors, motors driven by carbon dioxide and by ammonia, 

 cable traction, and electric motors. The descriptions 

 are not detailed enough to be entirely satisfactory, 

 nevertheless the volume contains a useful survey of the 

 condition and methods of automobile traction. 



M. Lecornu gives in his volume a detailed discussion 

 of the motions of governors of indirect and direct action. 

 His treatment of the various problems involved, and his 

 theorems on the conditions of equilibrium of different 

 governors will interest students of the mathematics and 

 mechanics of machinery. 



A Pocket Dictionary of Hygiene. By C. T. Kingzett, 

 F.I.C., and D. Homfray, B.Sc. Pp. 104. (London : 

 Bailliere, Tindall, and Cox, 1898.) 



This pocket-book is intended to be of assistance 

 to medical and sanitary officers in their work, by pro- 

 viding them with concise information upon subjects 

 comprehended in the theory and practice of hygiene. 

 The amount of information given is somewhat unequal, 

 and we should hardly have thought it necessary to in- 

 clude such definitions as : " Adipose, fatty. Anhydrous, 

 without water. Cardiac, pertaining to the heart. Caustic, 

 any substance which destroys animal tissue. Combus- 

 tion, the process of burning. Emanate, to issue or flow 

 from. Morbid, diseased or unwholesome," &c. Hertz's 

 name is spelt Herz, and Lenard is printed Lennard, in the 

 description of Rontgen rays. 



The Secret of the Poles. By Henry Campion. Pp. 48. 

 (Birmingham : White and Pike, Ltd., 1898.) 



Among the views advanced by the author in this booklet 

 are the following : — The earth is hollow— there is a 

 hollow region large enough to hide the moon and to 

 spare — the earth's axis is hollow — it has two openings, 

 one at each pole — meteoric swarms and ether are 

 attracted through the axis at the south polar entrance, 

 there producing the aurora australis, and after acting as 

 fuel for the fire in the interior is shot out as a waste 

 product at the north polar exit, where it produces the 

 aurora borealis. The character of the book is sufficiently 

 indicated by these extracts, which need no comment. 



Wireless Telegraphy., popularly explained. By Richard 

 Kerr, F.G.S. Pp. xv -t- iii. (London: Seeley and 

 Co., Ltd., 1898.) 



Mr. W. H. Preece expresses his general approval of 

 this little volume in a short preface ; but at the same 

 time he mentions that he does not accept any respons- 

 ibility for the controversial points raised. The author 

 explains the principles and practice of telegraphy without 

 intervening wires in words which will be found intelligible 

 by readers unfamiliar with electrical terms. His descrip- 

 tions possess the merit of being popular in style, and 

 the illustrations assist in brightening the text. 



NO. 1508, VOL. 58] 



LETTERS ^ TO THE EDITOR 



The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 viannscripts intended for this or any other part 0/ Nature, 

 No notice is taken of anonymous communications. 'I 



Chance or Vitalism. 



Prof. Japp's exceedingly interesting address on " Stereo- 

 chemistry and Vitalism " contains a direct challenge to those 

 who, like myself, hold that we can at present only remain agnostic 

 with regard to the problem of " the possibility or impossibility 

 of living matter originating from dead matter by a purely 

 mechanical process." Unfortunately the facts upon which he 

 bases his view, that chemical compounds of one-sided asymmetry 

 cannot arise save under the influence of life, touch a field so 

 much more familiar to him than to me, that it may seem pre- 

 sumption on my part to make one or two suggestions drawn 

 more directly from my own sphere of work. Still, to the 

 philosophical side of his reasoning I think Clifford, whom he 

 challenges, might, perhaps, have been ready with some reply. 

 I would first state what, I think, stripped of technical language, 

 and represented by the simplest case, is Prof. Japp's standpoint : 



(1) Optically active liquids are due to asymmetrical molecules. 



(2) These asymmetrical molecules arise from the replacement 

 in a symmetrical molecule of either a right-hand or left-hand 

 atom out of two equal atoms which are images of each other. 



(3) No optically active substance can be formed unless there 

 be a selection of purely right-handed or purely left-handed atoms, 

 or, at any rate, unless there be a sensible majority of one or of 

 the other. 



(4) Some asymmetric solvents have a power of selective 

 action on optically inactive mixtures of right-handed and left- 

 handed atoms, or, to use the technical term, of two enantio- 

 morphs. 



(5) No mechanical process (chemical or physical) could select 

 a right-handed as distinguished from a left-handed atom in a 

 symmetrical molecule, and so produce an asymmetric com- 

 pound. Any mechanical force which acts on a symmetrical 

 molecule is as likely to affect one atom in a molecule as its 

 image. If L be the selecting of a right-hand atom and IL of 

 a left-hand atom, then, as Prof. Japp puts it : 



" The chances in favour 01 these two events being equal, the 

 ratio. 



Number of occurrences of event L 

 Number of occurrences of event IL 



will, if we are dealing with an infinitely great number of mole- 

 cules, approximate to unity. We therefore obtain a mixture, 

 optically inactive by inter-molecular compensation." 



Now, putting on one side any objections to Prof. Japp's 

 reasoning arising from the fact that it is based on a purely 

 geometrical hypothesis as to the constitution of molecules, which 

 is also merely descriptive, for we can have no ultimate evidence 

 of its actuality'— I would draw attention to the fact that (5) is 

 an appeal to the doctrine of chance, and that Prof. Japp tells 

 us that the mechanical production of a left-handed or right- 

 handed enantiomorph is an event like the tossing of a coin, of 

 which the chances are precisely equal as to heads or tails. Now 

 if Prof. Japp will toss twenty coins, ten heads and ten tails will 

 undoubtedly be the most frequent result ; but there will be a 

 variation about this mean result, and if he goes on tossing long 

 enough he will ultimately come to an instance of twenty heads 

 or twenty tails alone. Cases in which there is a preponderance 

 of heads or tails of a very sensible kind will not be very in- 

 frequent. I take it that it is only a majority of left- or right- 

 handed enantiomorphs which is required to produce an optically 

 active substance. What majority might be easily ascertained 

 by delicate experiments on the rotatory power of mixtures of 

 dextro- and laevo-acids which are mirror-images of each other. 

 Now, according to Prof. Japp, chance is the factor at work in 

 the production of optically inactive mixtures of right- and left- 

 handed enantiomorphs. Hence, it may be in the course of 

 indefinite ages, purely mechanical action must certainly have 

 produced chemical compounds of one-sided asymmetry with 

 various degrees of rotatory power, due to the greater or less 



1 Such a ^ww^^wa/ hypothesis cannot give the ^^miwjVa/ explanation 

 of rotatory polarisation required by the physicist, and therefore the 

 " eminent physicist " quoted by Prof. Japp waSj I venture to think, right in 

 saying that an explanation of rotatory polarisation is still wanting. 



