NATURE 



25 



THURSDAY, NOVEMBER 14, 1895. 



THE EVOLUTION OF THE COSMOS. 

 Notes on the Nebular Theory in relation to Stellar^ 

 Solar, Planetary, Cometary and Geological Phenomena. 

 By William Ford Stanley, F.R.A.S., F.G.S., &c. 

 (London : Kegan Paul, Trench, Triibner, and Co., 

 Limited, 1895.) 



THE object of the present treatise is to establish in a 

 modified form the nebular theory of Laplace, by 

 the introduction of some original views which have long 

 occupied the attention of the author. This is an am- 

 bitious scheme, and it is a little disquieting to read that 

 authorities whose opinions carry weight did not recom- 

 mend the communication of these views to the learned 

 societies, whose duty it would have been to weigh and 

 consider them. The reason assigned is, that the views 

 were thought to be too speculative ; and after studying 

 them with great attention, we have no hesitation in saying 

 that we hold the advice to have been sound. 



Undoubtedly the nebular hypothesis as enunciated by 

 Laplace is on its trial, and does not recommend itself un- 

 reservedly to those most capable of judging its merits. 

 It may be admitted that a new working hypothesis would 

 demand and receive great attention. But emendations, 

 to be accepted, must come from those who have made a 

 profound study of mathematical and physical science, 

 and have proved themselves men of original genius. It 

 may be that Mr. Stanley has qualified himself to speak 

 with authority on this difficult subject, and undoubtedly 

 the many references quoted in his volume display 

 considerable reading and research ; but the references are 

 too frequently, not to original sources, but to the more 

 popular writings and expositions to be found in the Pro- 

 ceedings of the Royal Institution, or in the pages of Good 

 Words or the English Mechanic, and these authorities 

 are quoted, apparently with as much satisfaction as the 

 Philosophical Transactions. It is impossible to resist the 

 impression that the author's scientific information is 

 second-hand. The literary style of the work does nothing 

 to remove this impression, and is incompatible with a 

 complete mastery over the subject. Clearness of ex- 

 pression is wanting ; obscure passages, that tax the 

 patience of the reader, abound, and occasionally we come 

 across sentences that defy interpretation altogether. As 

 an example of these latter, we may give the following 

 (p. 42) :—" Assuming the pneuma to be a most perfect 

 fluid and elastic system of matter, upon the meeting of 

 two volumes of such matter, independently of any initial 

 rotation it might possess, must have moved under pres- 

 sure at the meeting plane in every or any direction, which 

 at the time offered the least resistance to the continuity of 

 its initial momentum." Obscurities such as these may 

 possibly prevent the presentation of the author's views 

 exactly as he would have wished. There are many 

 statements which we cannot accept, if we have properly 

 understood them, but which, expressed differently, might 

 command a ready assent. 



At the outset of his work, Mr. Stanley gives an his- 

 torical account of the distinguishing features of the main 

 cosmical theories, which have been elaborated by great 

 NO. 1359, VOL. 53] 



minds in the past. The author's want of grasp and 

 poverty of description are in this first chapter most 

 conspicuous. Instead of a full and lucid account of 

 these earlier ideas, which one would naturally expect 

 in a work of this character, the reader must be content 

 to find very meagre and obscure notes on the theories 

 of Descartes, of Kant, of Laplace, or of more modem 

 authorities, as Helmholtz, or of Faye. From this point 

 onward to the end of the book, the author devotes him- 

 self to the description of his own views and theories. 

 It has always been admitted, hitherto, by scientific men, 

 that nothing more than a partial solution of the problem 

 presented by the origin of the universe can possibly ever 

 be expected, and, certainly, that our present state of know- 

 ledge is inadequate to the task. Laplace, for instance^ 

 based his hypothesis on the assumed existence of the 

 sun, and sought to prove no more than the possibility 

 of the formation of a system of planets, such as we see 

 in existence. Mr. Stanley's theories are far more ambitious. 

 Not only does he seek to account for a state of things 

 existing prior to, and leading up to the formation of 

 the sun, but he undertakes to explain such details as 

 geological periods and the disposition of the materials 

 of the earth's crust. 



Following the theory which was first suggested by- 

 Wright of Durham, that the Milky Way forms one vast 

 originally connected system, Mr. Stanley imagines im- 

 mense districts in space filled with matter in its " original 

 state." This is assumed to be of an attenuated gaseous 

 character, and since the calculated size of the ultimate 

 atom would leave less than a single specimen to the 

 cubic metre, each one, for reasons which are not apparent,, 

 is divided into a large number of parts called "pneu- 

 mites," which in a state of perfect atomic dissociation 

 give rise to every line in the spectrum of light. The 

 form of the " pneumites " is described in detail ; but, inas- 

 much as our knowledge of the ultimate nature of the 

 atom itself is'confessedly imperfect, these speculations are 

 obviously useless from a scientific point of view. 



Having formed these arbitrary notions of the ele- 

 mentary condition of matter, existing at a high tem- 

 perature, Mr. Stanley proceeds to explain the origin 

 of the Milky Way as a vast agglomeration of pneu- 

 mites, to which he gives the name " pneuma," moving 

 in slow rotation. To account for the flattened form of 

 the Galaxy, it is suggested that two such spheroidal 

 " pneumas " drifted together at an early period, forming 

 at their common surface a somewhat denser plane, over 

 which the more distant parts of the pneumas would 

 spread themselves by the action of their original momenta, 

 while such parts as did not entirely combine would 

 cause an apparent bifurcation. The division of this 

 original " pneuma " system into nebulee, and ultimately 

 stellar systems, appears to be left to no more dignified 

 cause than chance, aided by condensations brought 

 about by heat radiation. The means by which it is sug- 

 gested that these bodies kept distinct can only be 

 described as obscure and unsatisfactory, and the attempt 

 to cover with a false appearance of reasoning what must, 

 by the nature of the case, remain matter for the vaguest 

 speculation and assumption, is altogether to be regretted. 



The author proceeds to discuss the behaviour of one 

 of these separate condensations which is taken as the 



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