October 25, 1894J 



NA TURE 



621 



Conway on the Alps, their limits, structure, and pbysiojnomy, 

 and Mr. C. Raymond Beazeley on a new Periplus of the 

 Erythrean Sea. Mr. J. Theodore Bent, who starts immediately 

 on a new journey from Oman to Aden across .\rabia, hopes to 

 return in time to give an account of his travels. The Christmas 

 lectures to young people will ba continued, the lecturer this 

 year being Dr. H. R. Mill, and the subject "Holiday 

 Geograpliy." 



We have received a new instalment of the "Annals" (Eje 

 godnik) of the Russian Geographical Society, vol. iii. 1894, 

 which is on the same high level as the preceding issues of the 

 same series. It contains a review of astronomical, geodetical, 

 and cartographical work done in the year 1892 by the geodetists 

 and topographers of the Ministry of War, and of the hydro- 

 graphic work done in 1891 by the officers of the Navy. The 

 meteorological and hydrological observations made by officers 

 of the Russian Navy are discussed by P. A. Mordovin ; and 

 also the work of the officers of the Ministry of Ways. E. E. 

 Leist gives a review of the work dine in the domain of terres- 

 trial magnetism, magnetic anomalies, and magnetic perturba- 

 tions in Russia ; S. N. Nikitin sums up the progress of geo- 

 logical exploration in the Russian Empire ; B. Y. Steznewski 

 deals with the progress of Russian meteorology ; and N. I. 

 Kunetsoff gives an elaborate review of the work done in the 

 domain of botanical geography in Russia, and partly also in 

 West Europe. All these papers are supplied with full 

 bibliographical indexes. 



I.\ the same "Annals," M. Nikitin, who is undoubtedly the 

 highest authority on the Glacial period in Russia, sums up our 

 present knowledge as regards the supposed inter-glacial de- 

 posits in East Europe. In his well-known work on the glacia- 

 lion of Russia, published in 1SS6, he pointed out that the theory 

 of a double glaciation is utterly inapplicable to that country, 

 and that, if a second glaciation really has existed in Europe, it 

 did not exist in Russia, which must have been free of ice during 

 the period when the ice is supposed to have invaded Kuropefor 

 a second time. True, a young geologist, M. Kiischtafowitsch, 

 announced, in 1891, the discovery of inter-glacial deposits 

 about Moscow, and his article had been quoted in West 

 Europe as a confirmation of the double glaciation theory; but 

 the following year, when his observations were made with 

 greater accuracy, he hastened to recognise that he had too 

 rashly built up his theory. M. Nikit in's opinion is, therefore, 

 that, although the whole question cannot yet be considered as 

 finally settled, there are no facts whatever which the theory of 

 .tn inter-glacial period in East Europe might be built upon ; 

 on the contrary, the facts point to a single glaciation. 



The gradual but somewhat tardy recognition of the part 

 played by motor elements in consciousness in the localisation of 

 objects in space, forms an interesting chapter in the history of 

 the progress of psychological interpretation. A valuable 

 contribution to this subject is to be found in a paper on the 

 localisation of sound, by Prof. Miinsterberg and Mr. A. H. 

 Pierce, in the current number of the Psychological Kez'iru). It is 

 based on a careful experimental investigation, and goes far to 

 establish Prof. Miinsterberg's theory, that the assigning of 

 direction to sounds rests upon the union of sensations of sound 

 and motor sensations, the latter originating from actual or 

 intended movements of the head in the direction of the 

 sounding body. The paper, which well illustrates the value of 

 experimental research in psychology, deserves the careful 

 attention of all those who are interested in the psychological 

 aspect of the problems of space. 



An investigation that furnishes a new point of view from 

 which to consider the undoubted Arachnid affinities of that 



morphological puzzle, the American king-crab, Li'mului, it 

 described in the Zeilschrift J. -viss. Zoologit, vol. Iviii. part I 

 issued last July. The author is Dr. .\. Jaworowski, of Lem- 

 berg, and he has traced out the dei'elopment of the so-called 

 " lung " in a spider, Trochosa singoriensis. He finds that this 

 organ does not arise directly as such, but is formed in ontogeny 

 by the secondary modification of a true trachea, which con- 

 sists at first of a funnel-shaped external or stigmatic chamber, a 

 common tracheal stem, and a bundle of delicate terminal 

 tubules, penetrating some distance into the body. The tracheal 

 tubes gradually atrophy, and on the walls of the external 

 chamber or air-sac, which considerably enlarges, arise a number 

 of parallel lamelliform folds, at right angles to the course of the 

 common tracheal stem. From these structures, which in their 

 early stages recall the appearance presented by the transverse 

 striations of the tracheae in insects, the respiratory lamelli of 

 the "lung" are derived. Development thus establishes the 

 Tracheate origin of the Arachnida, and opposes the view that 

 the lungs of spiders have arisen as modifications of the gill-books 

 of a Zm;//»j-like ancestor ; though Dr. Jaworowski holds that 

 the converse of this proposition — that the gill-books of Limulus 

 have been evolved by the modification of Arachnid lun js — is 

 very probably true. Simroth's view that Zi><«/«.t is essentially 

 a land animal, secondarily adapted to a marine existence, is 

 thus confirmed ; and Dr. Jaworowski does not hesitate, after a 

 discussion of the nature of the Crustacean gill, to derive the 

 whole phylum Crustacea from the Tracheate stem. 



Herren Kohlrausch and Ileydweiler appear to have 

 approximated more closely to the preparation of absolutely 

 pure water than any previous observers. In a paper on the 

 subject, published in the current number of Wiedemann s 

 Annalm, they describe the manner in which they prepared and 

 tested the samples of pure water. Water distilled in air shows, 

 even with the greatest precautions, an elec'.ric conductivity of 

 07 X 10""' at iS'C, mercury being the unit. Distillation in a 

 vacuum of aboat 001 mm. reduces this conductivity to 

 025 X 10"'"', but into this value the solubility of the glass 

 enters as a disturbing factor. A glass vessel employed for the 

 purpose ten years ago had been cinstantly kept filled with 

 water, with the result that the value for the conductivity found 

 with what was now piactically insoluble giass was as low as 

 0'04 X 10"'". This value was greatly influenced by changes of 

 temperature, being about o'oi4 at o', and O'lS at 50', but this 

 behaviour had been predicted by the theory of dissociation. 

 The authors now endeavoured to find the true conductivity of 

 absolutely pure water by extrapolation, on the b.asis of the 

 change of the temperature coefficient with increasing impurity, 

 as given by the theory of dissociation. The value thus obtained 

 for the conductivity of absolutely pure water at lS° C. was 

 0036 X 10"''. It will be seen that the extrapolation only 

 amounted to 10 per cent. The amount of residual impurity 

 was estimated at a few thousandths of a milligramme per litre, 

 which is lo,033 times less than the amount of air normally 

 absorbed from the atmosphere. A curious phenomenon 

 observed in the course of these measurements was the tem- 

 porary increase of conductivity of the water when the current 

 was of any considerable duration, an increase which sometimes 

 amounted to too per cent. The amount of dissociated 

 hydrogen in a cubic metre of water at iS' is calculated to be 

 ooS milligrammes, at o' only 0036 milligrammes, and at 100° 

 o'S5 milligrammes. Small as are these numbers, they still mean 

 thousands of millions of atoms to the cubic mm., i.e. intervals 

 between neighbouring atoms of the order of wave-lengths of 

 light. In our conception, and even in miscroscopic vision, 

 these free atoms of hy.irogen would still appear to fill space 

 continuously. That Ohm's law still holds for such a solution 

 is not surprising. 



NO. 1304, VOL. 50] 



