52: 



NA TURE 



[Sept. 28, 1882 



cules of the same substance are ' unalterable by the pro- 

 cesses which go on in the present state of things, and 

 every individual of the same species is of exactly the same 

 magnitude as though they had all been cast in the same 

 mould, like bullets, and not merely selected and grouped 

 according to their size, like small shot,' and that, there- 

 fore, as he expresses it in another place, they are not the 

 products of any sort of evolution, but, in the language of 

 Sir John Herschel, ' have the essential character of 

 manufactured articles.' " 



" Now, on what logical, mathematical, or other grounds 

 is the statistical method applied to the velocities of the 

 molecules in preference to their weights and volumes ? 

 What reason is given, or can be given, why the masses of 

 the molecules should not be subjected to the process of 

 averaging as well as their motions ? None whatever. 

 And, in the absence of such reason, the deductions of the 

 kinetic theory, besides being founded on rickety premisses, 

 are delusive paralogisms." 



" Upon these considerations I do not hesitate to de- 

 clare that the kinetic hypothesis has none of the charac- 

 teristics of a legitimate physical theory. Its premisses 

 are as inadmissible as the reasoning upon them is incon- 

 clusive. It postulates what it professes to explain ; it is a 

 solution in terms more mysterious than the problem — a 

 solution of an equation by imaginary roots of unknown 

 quantities. It is a pretended explanation, of which it 

 were unmerited praise to say that it leaves the facts 

 where it found them, and is obnoxious to the old 

 Horatian stricture : '///'/ agit exemplum, litem quod lite 

 resolvit.' " . . . . 



"It may seem strange that so many of the leaders of 

 scientific research, who have been trained in the severe 

 schools of exact thought and rigorous analysis, should 

 have wasted their efforts upon a theory so manifestly 

 repugnant to all scientific sobriety— an hypothesis in 

 which the very thing to be explained is but a small 

 part of its explanatory assumptions. But even the intel- 

 lects of men of science are haunted by pre-scientific 

 survivals, not the least of which is the inveterate fancy 

 that the mystery by which a fact is surrounded may be 

 got rid of by minimising the fact and banishing it to the 

 regions of the extra- sensible. The delusion, that the 

 elasticity of a solid atom is in less need of explanation 

 than that of a bulky gaseous body, is closely related to the 

 conceit that the chasm between the world of matter and 

 that of mind may be narrowed, if not bridged, by a rare- 

 faction of matter, or by its resolution into forces. The 

 scientific literature of the day teems with theories in the 

 nature of attempts to convert facts into ideas by a process 

 of dwindling or subtilisation. All such attempts are 

 nugatory ; the intangible specter (sic) proves more 

 troublesome in the end than the tangible presence. Faith 

 in spooks (with due respect be it said for Maxwell's 

 thenno-dynamical 'demons' and for the population of 

 the 'Unseen Universe') is unwisdom in physics no less 

 than in pneumatology." 



"Pure Being is simply the specter {sic) of the copula 

 between an extinct subject and a departed predicate." 

 It is a pity that a man who can so smartly show up the 

 absolute nonsense of the professed metaphysicians (past 

 and present alike) should weaken the force of his really 

 valuable remarks by attacking in a similar style some of 

 the best-ascertained truths of mathematical and of physi- 

 cal science. We repeat that the volume is lively reading, 

 that its smartness is visible in every page, but that its 

 author (having once been bitten by metaphysics) has, in 

 his desire to save others, run a-muck not merely through 

 gossamer webs but also against stone walls. No doubt 

 he has done good : — some of the supposed stone walls he 

 has encountered have proved to be mere stage "proper- 



ties." But the reader cannot fail to doubt the validity of 

 a method which upsets with equal ease the most irre- 

 fragable truth and the most arrant nonsense. 



P. G. T. 



OUR BOOK SHELF 



Amazuluj the Zulus, their Past History, Manners, 

 Customs, and Language, with Observations on the 

 Country, and its Productions, Climate, eW.y the Zulu 

 War, and Zululand since the War. By the Rev. T. 

 B. Jenkinson. (London : W. H. Allen and Co., 1882.) 

 The Rev. Thomas B. Jenkinson, having been a mis- 

 sionary in Natal between the years 1873-79, proposes to 

 give us his experiences of the country and its people in a 

 work bearing the above ambitious title. But so little 

 information is to be gleaned from its pages on these sub- 

 jects that the judicious reader will do well to begin and 

 end with the short appendix, which contains a few 

 remarks on the present political situation of Zululand. 

 This appendix consists of extracts from two letters not 

 written by Mr. Jenkinson, and nearly the whole of the 

 book is found to be made up in the same way of 

 quotations from diaries and private letters written by the 

 missionary or members of his family to friends in Eng- 

 land, or else of stale passages from the Cape Argus, Living- 

 stone's journals, Macmillan's Magazine, or the diaries 

 of other missionaries, who flourished half a century ago. 

 Thus the section devoted to "Historical Notices of the 

 Zulu Nation " consists largely of extracts from the journal 

 of the Rev. Francis Owen, originally published in the 

 Missionary Register for 1838 ! Deducting these whole- 

 sale appropriations, the actual amount of text attri- 

 butable to the compiler will occupy a very small portion 

 of the work. This, however, may be regarded as fortu- 

 nate, for the quantity is not compensated by the quality 

 of the composition, which is written in a crude, jerky 

 style, and made up mainly of trivial incidents of mis- 

 sionary life. The contributions to science and history 

 are remarkable, as, for instance, the statement that 

 " the British exchanged Java for St. Helena with the 

 Dutch 1 " (54) ; that the Zulus are somehow connected 

 with Israel, although they seem to be descended from 

 Ham, "still a common name among them "(33); that 

 the Zulu language " resembles" the Hebrew (18); that 

 in Natal there is a curious animal " called a rock-coney 

 rabbit, a rhinoceros in miniature!" (8); and that Mr. 

 Jenkinson "killed ten of those large rock-pigeons with 

 one shot" (188). A. H. K. 



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 luriters of, rejected manuscripts. 

 No notice is taken of anonymous communications. 



[ The Editor urgently requests correspondents to keep their letters 

 as short as possible. The pressure on his space is so great 

 that it is impossible otherwise to ensure the appearance even 

 of communications containing interesting and novel facts. ] 



Lighthouses 



In Dr. Siemens's inaugural address to the British Association, 

 reported in Nature, vol. xxvi. p. 398, reference is made to the 

 system originally suggested by Sir William Thomson some 

 years ago, " of distinguishing one light from another by flashes 

 following at varied intervals." 



Now in Sir William's article "On the Lighthouses of the 

 Future," in Good Words, March 1873, it is shown that the pro- 

 posal to distinguish lighthouses from each other by diverse 

 groups of occultations had been made by Charles Babbage at 

 least so early as 1S51 ; while, more recently, Capt. Colomb had 

 adopted intervals of unequal length for a code of signals corre 

 sponding to the Morse Telegraph Alphabet. This, however, 

 was, as I understand, for ships' night signals, and not for light- 

 house purposes. 



