January 21, 1892] 



NA TURE 



269 



neglected the old ; and whether a combination of what 

 is sound and true in both may not rather be needed in 

 order to attain the whole truth. It is doubtful whether 

 supply does not react upon demand as much as demand 

 on supply ; whether the consideration of disutility, 

 implied in the conception of cost of production, is not 

 equally important with that of utility, and equally de- 

 serving of distinct investigation ; whether, in fine, the 

 efforts and exertions of producers to supply wants are not 

 as potent a factor in advancing civilization, and as creative 

 of new wants, as the pressure of wants and desires them- 

 selves. The Austrian writers allow so much — though 

 perhaps they here exhibit some lack of distinct statement — 

 to the influence of " costof production," that they might, it 

 would seem, go a little further, and place it on an equality 

 with the principle of marginal utility. They would then, 

 perhaps, recognize what Prof. Marshall, in his broader, and, 

 as it appears to us, more philosophic, exposition of value, 

 calls the fundamental symmetry of the laws of the forces 

 working on both sides, which is exhibited in the analogy 

 between " marginal utility " and " marginal cost of produc- 

 tion," and a law of "diminishing returns" and one of 

 " decreasing utility." They would, in short, without sacri- 

 ficing altogether the vast amount of trouble bestowed by 

 Ricardo and his followers on one side of the problem, assign 

 a proper, and not an exclusive, emphasis to the side which 

 they had themselves done so much to elucidate. For 

 these reasons we consider Mr, Smart's modest conclusion 

 — that " the last word on value has not been said by the 

 Austrian school" — to be as sound and as pertinent, as his 

 exposition of their views is clear, pointed, and suggestive. 



OUR BOOK SHELF. 



Across Thibet. By Gabriel Bonvalot. Translated by C. 

 B. Pitman. Two Vols. (London : Cassell and Co., 

 1891.) 



Aftf:r the return of M. Bonvalot and Prince Henry of 

 Orleans from the East, so much was said of their journey 

 that we need not now repeat any of the details of M. 

 Bonvalot's narrative. It may suffice for us to commend 

 the book very cordially to the attention of readers who 

 like to wander in imagination with travellers in remote 

 parts of the world. M. Bonvalot, as his translator says, 

 has those qualities of courage, self-command, tenacity, 

 knowledge of human character, and good humour, which 

 go to make up the successful traveller ; and he writes of 

 his achievements so simply and naturally that there is 

 nothing to interfere with the reader's full enjoyment of 

 his story. The travellers, as everyone interested in geo- 

 graphical exploration will remember, started from the 

 frontiers of Siberia, and in the course of the journey which 

 brought them to Tonquin passed right through Tibet. 

 Their route lay to some extent over ground which no 

 European had ever before traversed, and this is, of 

 course, the portion of his subject on which M. Bonvalot 

 writes most carefully and effectively. The work has been 

 translated in a clear and pleasant style, and it is enriched 

 with many interesting illustrations. 



LioJit. By Sir H. Trueman Wood. " Whittaker's Library 

 of Popular Science." (London : Whittaker and Co., 

 1891.) 

 We have here a popular and interesting account of many 

 of the facts relating to the nature and properties of light. 

 The subject is treated in a way that will induce many 

 readers to glance through its pages, even if they do not 



NO. 1 1 60, VOL. 45] 



more carefully peruse it ; while many a more advanced 

 student will read the chapters on double refraction and 

 polarization, lenses, and interference and refraction. Of 

 other points touched on, we may mention spectrum 

 analysis, optical instruments, chemical effects of light, 

 fluorescence and phosphorescence — all of which are 

 delightfully treated by the author. 



In the appendix will be found a list of the more ele- 

 mentary and popular works on the subject, which should 

 prove useful to those who wish to extend their knowledge. 



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 

 manuscripts intended for this or any other part of Nature.. 

 No notice is taken of anonymous communications. "^ 



Opportunity for a Naturalist. 



Will you allow me to say that the letter which you kindly 

 inserted under this head in your issue of December 24, 1891 

 (p. 174), has brought me many replies? After considering 

 them, I have made arrangements with Mr. O. V. Aplin (mem- 

 ber of the British Ornithologists' Union, and author of "The 

 Birds of Oxfordshire") to proceed to Uruguay in August next. 

 Mr, Aplin will reside for six months on an estancia in the pro- 

 vince of Minas, and devote himself primarily to birds, but will 

 also collect insects and plants. P. L. Sclater, 



3 Hanover Square, W. 



Dwarfs and Dwarf Worship. 



In the slow course of post in this Protectorate I have just 

 received copies of the Times of September 3 containing Mr, R. 

 G. Halliburton's paper on " Dwarf Races and Dwarf Worship," 

 and of September 14 and 22, containing subsequent correspond- 

 ence on the same subject. Having crossed the Atlas Mountains 

 at several different points, and approached the district which is 

 indicated by Mr. Halliburton as the original home and hidden 

 sanctuary of his diminutive and venerated people, I have read 

 his paper with much interest and may perhaps be permitted to 

 criticize his conclusions. My chief during my expedition to 

 Morocco, that distinguished traveller Mr. Joseph Thomson, is, 

 I believe, at present in Katanga, and therefore more inaccessible 

 than I am ; but when he is able to -speak on the subject, his 

 judgment on the case which Mr. Halliburton has very elaborately 

 set up will not, I am confident, be different from mine. 



Mr. Halliburton begins with a statement that is at once 

 startling and decisive. The information he has collected puts it, 

 he says, beyond question that there exists in the Atlas Moun- 

 tains, only a few hundred miles from the Mediterranean, a race 

 of dwarfs only 4 feet high, who are regarded with superstitious 

 reverence or are actually worshipped, and whose existence has 

 been kept a profound secret for 30CO years. Such an emphatic 

 assertion ought to rest on clear and irrefragable evidence ; and I 

 read Mr. Halliburton's paper in constant expectation of the 

 proofs of his remarkalile discovery, but reached the end of 

 it without coming on a shred of testimony in support of his 

 contention, of the slightest value to anyone acquainted with 

 Morocco and the Moors. The paper is highly discursive, and 

 abounds in what seem to me far-fetched and irrelevant specu- 

 lations, on the connection between ancient Moorish poems and 

 Greek mythology, on the derivation of the Phoenician deities, 

 and on the meaning of Moorish habits and customs ; but the 

 only evidence, confirmatory of its thesis, adduced in it and in 

 Mr. Halliburton's subsequent letters, amounts to this : that six 

 Europeans have seen dwarfs in Morocco ; that an indefinite 

 number of natives have romanced about dwarfs in their usual 

 way ; that there are in Morocco artificial caves — presumably 

 dwellings — of such small size as to suggest that they must have 

 had very short inhabitants ; and that there have come down to us 

 from antiquity traditions as to Troglodytes who dwelt in the 

 Atlas Mountains. 



Mr. Halliburton's European witnesses are unimpeachable ; 

 and had my friend Mr. Hunot, whose knowledge of the 

 country is extensive and accurate, distinctly said that there is a 

 race of dwarfs in Morocco, I should not have ventured to con- 



