68 



NATURE 



[A/ay 25. 1876 



cruise down the Sea of Aral, and up the Amu, and, as we 

 have said, a journey across the dreary desert of Kizzel 

 Koom. Major Wood conveys, we think, a clearer and 

 more vivid idea of the region indicated, its aspects, and its 

 inhabitants, their characteristics and habits, than any 

 other author we know. The maps which accompany the 

 volume are a great assistance. We may note that they give 

 the present level of the Caspian as 85 feet below that of the 

 ocean. Lake Aral being 158 feet above sea-level. This, 

 we presume, may be taken as authoritative for the present, 

 and it ought to be noted, as the statements on the point in 

 various authorities differ in a most remarkable way. 



Major Wood naturally speaks of the conduct of Russia 

 in Asia with warm approval, and indicates several bene- 

 ficial results which have followed her recent conquests. 

 He believes that of all European powers she, partly from 

 the simplicity of her Government, and partly on account 

 of her ethnic affinities, is best suited to wean the wan- 

 dering hordes of Central Asia to a settled and civilised 

 life. We strongly recommend Major Wood's work as one 

 of substantial value and great interest. But why has a 

 work of such importance and so full of details, been 

 allowed to go forth without an index. We hope this 

 omission will be remedied at the first opportunity. 



OUH BOOK SHELF 



La Thioris des Plantes Carnivores et Irritables. Par 



Edouard Morren. (Bruxelles : F. Hayez, 1876.) 

 In this pamphlet, a report of an address given at the an- 

 nual public meeting of the scientific section of the Royal 

 Academy of Belgium, on Dec. 16, 1875, Prof. Morren gives 

 an admirable rC'SJiin^ of the present state of our know- 

 ledge on these two branches of vegetable physiology. As 

 regards the now well-known phenomena of carnivorous 

 plants, he gives the most essential points of the obser- 

 vations of Darwin, Hooker, Lawson Tait, Reess and 

 Will, the author himself, and others : and, in contrast to 

 his relative, M. Charles Morren, he gives his full adhe- 

 sion to the view that nitrogenous substances are actually 

 digested by the leaves of Drosera, Pinguiciila, and Ne- 

 penthes. He points out, indeed, that the theory is not a 

 new one, having been promulgated by Burnett in 1829, as 

 respects Sarracenia; and by Curtis in 1834, and Canby 

 in 1868, as Xo Dio7icpa; and also, he might have added, 

 by Dr. Lindley, in his " Ladies' Botany," published in 

 1834. In his introductory remarks Prof. Morren insists 

 on the identity of the process of nutrition in the animal 

 and vegetable kingdoms. The second portion of the 

 discourse is devoted to the elucidation of the pheno- 

 mena of " Motility " as exhibited in the irritability of the 

 leaves of Mimosa, the stamens of Berberis, and other 

 organs which exhibit similar peculiarities ; the aggregation 

 of protoplasm as seen in the " tentacles " of Drosera ; 

 the apparently spontaneous movements of zoospores, 

 climbing plants, &c. Anyone desiring to obtain a general 

 idea of what is at present known on these interesting 

 subjects could not do better than consult Prof. Morren's 

 lecture. It is pleasant to find a tribute to "la science 

 Anglaise " in connection with vegetable physiology. 



A. W. B. 



LETTERS TO THE EDITOR 



[ The Editor does not hold himself responsible for opinions, expressed 

 by his correspondents. Neither can he undertake to return, 

 or to correspond with the -writers of, rejected manuscripts. 

 No notice is taken of anonymous communications.^ 

 Supposed New Laurentian Fossil 

 When a man finds that he has made a mistake, the best thing 

 he can do is frankly to acknowledge and explicitly to correct it. 



I lose no tune, therefore, in making known to the readers of 

 Nature that the notice of a New Laurentian Fossil which I 

 published in its columns three weeks since, was written under a 

 complete misapprehension of the real nature of the body. So 

 far from being calcareous, as I had been led to believe by the 

 information I had received from the geologist who found the 

 specimen, it proves to consist of alternating layers of felspar and 

 quartz — the former simulating an organic structure like that of 

 Stromatopora, and the latter occupying what had been supposed 

 to be the cavities of that structure — together constituting what is 

 known to petrologists as "graphic granite." 



The conclusions I had drawn from a carsory examination of 

 the sections first sent me by Mr. Thomson, instead of being con- 

 firmed by a more minute study of thinner sections, proved to be 

 altogether untenable; what I had supposed to be piles of flattened 

 chamberlets in the thickness of each lamella, turning out to be 

 mere fissures in the felspar, arranged with extraordinary regu- 

 larity ; and what had seemed to be a vertical tubular structure, 

 proviiig to be mere striation. 



The examination of numerous sections of this body, and a 

 comparison of them with sections of the " graphic granite" found 

 in its neighbourhood, has now satisfied me that the former pre- 

 sents no other indication of organic origin, than is afforded by the 

 6Vwwa/c?/^ra-like disposition of its alternating lamellce ; andthit 

 this is so nearly approached in the latter, as to show that the 

 agencies which produced the "graphic granite " were competent 

 to have produced the supposed flarris fossil. 



Whether these agencies were entirely inorganic, or whether 

 the "graphic granite" itself may not be a metamorphic form of 

 an ancient organic structure (metamorphoses nearly as strange 

 having undoubtedly happened), is a question which is not at 

 present to be decided by anyone's ipse aixit. When a petrolo- 

 gist shall have succeeded in making a graphic granite, he will be 

 entitled to speak with assurance of its purely mineral nature. 



It will doubtless be triumphantly urged by those who maintain 

 Eozdon to be a "pseudomorph," that as I have had to confes-s 

 myself completely mistaken in regard to the Harris specimen, I 

 am just as likely to have been wrong in regard to the Canadian 

 ophicalcite. To this I have simply to reply that my mistake in 

 the present case has arisen entirely from undue haste, and has 

 been corrected by my own more careful .study ; which hai 

 satisfied me of the entire absence, in the Harris specimen, of 

 those Foraminiferal characters which seem to me unmistakably 

 recognisable in the Canadian Eozoon. 



In the memorable discussion at which I was present in Pari?, 

 on the flint implements found associated with the Abbeville jaw, 

 it was the entire absence, on the surface of those worked flints, of 

 the staining, the dendrites, the patina, and the wearing of the 

 edges, characteristic of the genuine implements, which satisfied 

 the English experts of the factitious character of the former. 

 But, so lar from anyone being led by this discussion to call in 

 question the fashioning of the genuine implements by men coeval 

 with the river-gravels of the Somme, it only brought out more 

 fully the strength of that case, by showing what complete reliance 

 might be placed upon the characters of antiquity which they pre- 

 sented. And so, in the present instance, the striking contrast 

 in the microscopic appearances presented by two bodies bearing 

 a close resemblance in general structure, seems to me only to 

 bring out the organic characters of the one more decidedly, by 

 comparison with the purely mineral characters of the other. 



William B. Carpenter 



Theory of Electrical Induction 



I WAS hoping someone of eminence would tell us what he 

 thought of the arguments of Prof. Volpicelli, or whether nj 

 clearer view of induction had been arrived at. Prof. Clerk 

 Maxwell's letter of last week brings back the subject to its natural 

 point of view to one whose ideas are based upon potential, but 

 at the same time it leaves some points doubtful which have a 

 particular bearing on the whole theory. Might I therefore be 

 allowed to ask information from him, by explaining the ideas 

 which have been impressed upon me about this, by reading his 

 book "Electricity and Magnetism," though they are removed 

 toto cceIo from the ideas expressed by the phraseology of Prof. 

 Volpicelli, and that of the usual text-books. 



We know nothing of electricity except as a force. We may 

 speak of it as a fluid, and use a corresponding terminology, but 

 it is always measured as force. A conductor is a body in which 



