96 



NA TURE 



[May 26, 1887 



density, about 4. — Contribution to the study of the alkaloids, 

 by M. Oechsner de Coninck. Having in a previous paper 

 described the reaction of potassa on a combination of the iodide 

 of ethyl with nicotine, the author here confirms by a fresh line 

 of observation the relation of nicotine to the pyridic and 

 dipyridic series. — On some fossil woods found in the Quaternary 

 formations of the Paris basin, by M. Emile Riviere. These 

 specimens were found associated with the animal remains already 

 frequently described by the author. A microscopic study has 

 enabled him to determine three different vegetable species : 

 Palm, Cedroxylon, and Taxodium. The last-mentioned was 

 especially abundant in the Miocene epoch, and appears to be 

 older than the non-fossilized specimens from time to time dis- 

 covered in the boggy districts of Switzerland. 



Berlin. 



Physical Society, April 22. — Prof. Du Bois-Reymond, 

 President, in the chair. — Dr. Gross explained his theoretical 

 views on the heat of solution of magnetised iron, and showed 

 why, in accordance with these, the heat of solution of magnetised 

 iron must be greater than that of unmagnetised. One result of 

 these views was that a piece of magnetised and unmagnetised 

 iron in a conducting fluid capable of dissolving the iron must 

 give a current ; this he has already demonstrated two years ago 

 (see Nature, vol. xxxi. p. 596). The current in such an element 

 as this flows across the fluid from the magnetised to the unmag- 

 netised pole, and is independent of the nature of the magnetisa- 

 tion. The source of the electric current is in this case, according 

 to the views of the speaker, to be sought for in the loss of specific 

 magnetisation which the molecules of iron undergo as they pass 

 from the solid to the fluid condition. Of the various solutions 

 of salts of iron which were used in these experiments, only 

 neutral salts of ferric oxide were found to yield a result, while 

 the salts of ferrous oxide gave no current. The cause of this is, 

 according to the speaker, that only the ferric salts lead to a 

 solution of the magnets. Dr. Nichols has quite recently carried 

 on some experiments on the heat of solution of magnetised iron, 

 and has obtained the same experimental results, namely that the 

 heat of solution of magnetised iron is greater than that of un- 

 magnetised, although he starts with theoretical views respecting 

 the magnetic potential of solid iron and iron in solution which 

 are diametrically opposed to those of Dr. Gross. — The President 

 exhibited a Bourdon's manometer, and explained its use for the 

 measurement of alterations of blood-pressure in living animals. 

 In connexion with this the President gave a full account of the 

 physical portions of the research which Dr. Grunmach has 

 carried out on the influence of elasticity on the rate of progres- 

 sion of the pulse-wave. The most important points of this 

 research have already been communicated in the report of the 

 last meeting of the Physiological Society on April 15 (Nature, 

 May 12, p. 48). 



Physiological Society, April 29. — Prof. Du Bois-Reymond, 

 President, in the chair. — Dr. Onodi, of Buda-Pesth, gave an 

 account of the anatomical investigations which he carried on 

 during his two visits to the Zoological Station at Naples. In 

 the first place he busied himself with the anatomy of the ciliary 

 ganglion, which he examined microscopically in twenty-five 

 different species of Selachians. From what he found in these 

 lower vertebrates, as well as from observations which he had an 

 opportunity of making on the embryos of cartilaginous fishes 

 and chicks, he has come to the conclusion that the ciliary 

 ganglion must be reckoned in with the sympathetic plexus. In 

 addition to the above researches Dr. Onodi was occupied with 

 investigations on the roots of the vagus, and he communicated a 

 number of interesting details on their relations in the Selachians. 

 — Dr. Konig spoke on Newton's law of colour-mixing, explain- 

 ing its principle, and illustrating it with the aid of a Newton's 

 colour-chart. He then developed the three propositions which 

 Grassmann has deduced from the Newtonian law, and which, 

 as is well known, are as follows : (i) when two spectral colours 

 are mixed the resulting compound colour is a spectral colour 

 lying between the other two, but mixed with white ; (2) when 

 one of the two colours which is being mixed is continuously 

 changing, then the resulting compound colour also changes con- 

 tinuously ; (3) similar colours when mixed give similar compound 

 colours. Of these three propositions the first has not been con- 

 firmed by later experimental researches, but this does not 

 diminish the value of Newton's law of the mixing of colours : it 

 only becomes necessary to substitute a triangular colour-chart 



for the circular one put forward by Newton. The second pro- 

 position was fully confirmei by experience. The third proposi- 

 tion, which may also be expressed by saying that the compound 

 colour is independent of the intensity of its separate constituents, 

 was not confirmed by experiments. The speaker has alone, and 

 in conjunction with Herr Breduhn, carried out careful measure- 

 ments on trichromatic and dichromatic eyes, and has always 

 observed a difference in the compound colour as the result of 

 marked differences in intensity of the compounded colours. 

 The validity of Newton's principle in its general form is therefore 

 considerably shaken by this discovery, and must be confined to 

 narrow limits of variations of intensity. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED. 



The Agricultural Pests of India : Surgeon-General E. Balfour (Quaritch). 

 — Schriften der Naturforschenden Gesellschaft in Danzig (Danzig). — The 

 Storage of Electrical Energy: G. Plante (Whittaker). — Manual of Bacte- 

 riology : E. M. Crookshank (Lewis). — Chance and Luck : R. A. Proctor 

 (Longmans) — Manual of Scientific Inquiry, 5th edition : edited by Sir R. S. 

 Ball (Eyre and Spottisvvoode). — Elementary Trigonometry : Rev. T. Roach 

 (Clarendon Press, Oxford).— Our Bird Allies: V. Wood (S.P.C.K.).— Dan- 

 delion Clocks : J. H. Ewing (S.P.C.K.).— Agriculture in some of its Rela- 

 tions with Chemistry, 2 vols. : F. H. Storer (Low). — The Fungus-Hunter's 

 Guide : W. D. Hay (Sonnenschein). — Forestry of West Africa : A. Moloney 

 (Low). — Shores and Alps of Alaska : H. W. Skarr (Low). — The Races of 

 the British Isles (Quaritch). — Rousdon Observatory, vol. iii. , Meteorological 

 Observations for the Year 1886 : C. E. Peek. — Transactions of the Seismo- 

 logical Society, vol. x. (Yokohama). — New Commercial Plants and Drugs, 

 No. 10: T. Christy. — (Quarterly Journal of the Geological Society, vol. xliii,, 

 part 2, No. 170 (Longmans). — Bulletin of the American Geographical Society, 

 1886, No. 3 (New York). 



CONTENTS. PAGE 



Treatment and Utilisation of Sewage 73 



The Polyzoa of the Challenger Expedition 74 



Our Book Shelf:— 



Lock: "Dynamics for Beginners" 75 



Temple: "Journals kept in Hyderabad, Kashmir, 



Sikkim, and Nepal" 75 



Letters to the Editor : — 



Sunlight Colours. — Prof. S. P. Langley 76 



The Eclipse of August 19, 1887.— Dr. A. Woeikof . 77 



Iridescent Clouds. — T. W. Backhouse 77 



Remarkable Hailstones. — Rev. A. Irving 77 



The Orbit of the Minor Planet Eucharis. — Dr. W. 



Valentiner 77 



A Question for Chemists. — Harry Napier Draper . 77 

 "A Junior Course of Practical Zoology." — Prof A. G. 



Bourne 77 



" On the Establishment of the Roman Dominion in 

 South-East Britain."— Sir G. B. Airy, K.C.B., 



F.R.S 78 



Flora of Christmas Island. By W. T. Thiselton 



Dyer, CM. G., F.R.S 78 



The Journal of the Royal Microscopical Society — 



Retrospective and Prospective 78 



Bridging the Firth of Forth, By B. Baker. {Illus- 

 trated) 79 



Upper Wind-Currents near the Equator, and the 

 Diffusion of Krakatab Dust. By Hon. Ralph 



Abercromby. {Illustrated) 85 



Bernard Studer 87 



Notes 87 



Our Astronomical Column : — 



Photography the Servant of Astronomy 90 



A New Minor Planet 90 



Comet 1887 ^ (Barnard, 1887 May 12) 90 



Astronomical Phenomena for the Week 1887 



May 29 — ^June 4 90 



Geographical Notes 91 



On Zircons and other Minerals contained in Sand. 



By Allan B. Dick 91 



The Rolling Contact of Bodies. By Prof. Hele 



Shaw 92 



A Remarkable Meteor 93 



Scientific Serials 93 



Societies and Academies 93 



Books, Pamphlets, and Serials Received 96 



