544 



NATURE 



[April 19, 1877 



the latter of which is absorbed; and on the latter theory, 

 light acts mechanically on the molecule, shifting the posi- 

 tions of the atoms. Poitevin has done much to confirm the 

 former of these hf placing a film of silver iodide in contact with 

 a silver plate, when he succeeded in obtaining an ima;^e on the 

 film of iodide and one on the silver plate produced by the liber- 

 ated iodine. Capt. Abaey has performsd the following experi- 

 ments : a portion of a dry plite which had been exposed, was 

 wet with a sensitive collodion emulsion of bromide of silver, and 

 developed by the alkaline method ; the film? were separated 

 from the glass and from each other by means of gelatinised 

 paper, and were foand to bear images : and the same result 

 was obtained when the emulsion was added after exposure, 

 development, and fixing. These experiments entirely disprove 

 the supposition that only those molecules acted on by light are 

 reduced. If the two films be separated by a thick layer of 

 albumen, the lower picture develops as a negative, and the 

 upper as a positive. Capt. Abaey is now engaged in an attempt 

 to determine the attraction exercised by the sub-bromide, and 

 this it is hoped, will do much towards the complete solution of 

 the problem of the photographic imige. — Mr. O. J. Lodge pro- 

 posed a modification of Mance's method for determining the in- 

 tensity of an electric current. This method, of which Wheat- 

 stone's Bridge is an application, depends upo.i the fact that if 

 three conductors hi united at a point A, and their extremities 

 B C and D be united by three wires, B C, CD, D B, the re- 

 sistance o{ B C will be independent of that oi A D'xi A B is to 

 A C z.% B D IS, to J^D. In the arrangement proposed by Mr. 

 Lodge, four wires are joined in the form of a square, and the 

 circuit ct.n be completed across one diagonal by means of a key, 

 and in the other diagonal is included a condenser and a galvano- 

 meter, with a long fine wire. The greatest sensitiveness is 

 obtained when the resistances in the four sides are equal. A 

 great advantage of this method consists in the (act that it is 

 equally applicable to the measurement of small and great resist- 

 ances. Mr. Lodge then showed a modified form of Daniell's 

 cell, capable of giving a constant current for a considerable 

 period. A glass cell half filled with dilute sulphuric acid, con- 

 tains tVk'o vertical glass tubes one of v/hich, open at both ends, is 

 traversed by a zinc rod, while the other is closed at its lower end, 

 and contains cupric sulphate, from which rises a copper wire. 

 The portion of the glass tube projectiiig above the acid is 

 sufhcitntly moist to enable the current to traverse its surface 

 while the zinc sulphate is prevented from reacting on the copper. 

 Victoria (Philosophical) Institute, April 18. — Rev. R. 

 Thornton, D.D., vice-president, in the chair. — A paper on 

 recent Assyrian research, and the light it threw on civilisation at 

 the time of Abraham, was read by the Rev. II. G. Torakins. 



Manchester 



Literary and Philosophical Society, March 20. — Mr. E. 

 W. Binney, F.R.S., president, in the chair. — On the action of 

 sea-water upon lead and copper, by Mr. William H. Watson, 

 F.C.S. Communicated by Dr. R. Angus Smith, F.R.S.— Note 

 on the Upper Coal Measures of Canobie, Dumfriesshire, by Mr. 

 E. W. Binney, president, F.R. S. — Losses and gains in the 

 death-toll of England and Wales during the last thirty years, by 

 Mr. Arthur Ransome, M.D. 



Paris 



Academy of Sciences, April 9. — M. Peligot in the 

 chair. — The following papers were read : — On the possibility 

 of deducing from one only of the laws of Kepler the principle of 

 attraction, by M. Bertrand. — Some of the fundamental data of 

 thermo-chemistry, by M. Berlhelot. He deals with the heat of 

 formation of sulphurous acid and the compounds formed by bro- 

 mine and iodine with hydrogen and oxygen. — On a theorem 

 relative to the expansion of vapours without external work (con- 

 tinued), by M. Him. — Morphological relations between the 

 anthendia and the sporules developed in the verticiliate ramifi- 

 cation of a particular form of Battachospirmum moniliforme, 

 by M. Sirodot. — Substitution of chlorophyll for salts of copper 

 ordinarily used in preparation and conservation of fruits and 

 green vegetables, by M. Guillemare. This is based on three 

 tacts: (l) the chlorophyll of vegetables disappears in boding; 

 (2) vegetable fibre and its feculant nratter put in contact, 

 through washing, with dissolved chlorophyll, is saturated 

 with it near loo ;° (3) vegetables wholly or half saturated 

 with chlorophyll, in washing, thenceforth retains, in boil 

 ing, this green matter. — On the presence of zinc in the bodies 

 of animals and in plants, by MM. Lechartier and Bellamy. A 

 man's liver weighing 1,780 grammes contained 2 centigrammes 



of oxide of zinc ; 913 grammes muscular tissue of ox contained 

 3 centigrammes ; 1,152 grammes of hens' eggs 2 centigrammes. 

 Zinc was found also in grains of wheat, American maize, barley, 

 winter vetches, and white beans ; whde beet, the stems of maize, 

 green clover and its seed did not contain it in perceptible qaan- 

 tity. These facts have an important bearing on toxicological 

 researches. — Discovery of a Gallo-Roman port and a Gaulish 

 port, dated by a study of the layers of mud, in the neighboarhood 

 of Saint Nazaire, by M. Bertrand. M. Gervais added some 

 details. — Reconstitution of French wine-growing by sulphocar- 

 bonate of potassmm, by M. Mouiliefert. — Results obtained in 

 the treatment of phylloxerised vines by alkaline sulphoearbonates, 

 apphed by means of the distributing pale, by M. Gueyrand. — 

 Note on a new mode of manufacture of sulphides, carbonates, 

 and alkaline salphocarbonates, by M. Vincent. He utilises the 

 reactions produced in making beet sugar to prepare sulphide of 

 barium. This, mixed with sulphate of potash, gives by double 

 decomposition sulphate of baryta and sulphide of potassium, and 

 the latter, sub.iaitted to the action of carbonic acid gives car- 

 bonate of potassium. M. Vmcent extends his method to manu- 

 facture of sulphocarbonate, which he can obtain at 50 francs 

 the kilogramme instead of 120, which it has lately cost. — 

 List of thirty new nebulae discovered aad observed at the 

 observatory of Marseilles, by M. Stephan. — On a modification in 

 the employment of electricity considered as agent of galvanic 

 deposits and chemical decompositions, by M. Thenard. Instead 

 of having only one bath with the two anodes, the conditions 

 being those of small electric resistanee and maximum effort, he 

 has several, connecting their anodes like the elements of a battery 

 connected for tension. The quantity of deposited copper in- 

 creases with the number of baths, — New method for establishing 

 the equivalent in volumes of vaporisable substances, by M. 

 Troost. Given an inclosure filled with vapoar of hydrate of 

 chloral, then if the water is always combined, the atmosphere 

 will behave as if it were dry in presence of a body capable of 

 yielding water ; if the water is simply in mixture the atmosphere 

 will act as if saturated. Now the former occurs, and this con- 

 firms M. Dumas' hypothesis as against that of M. Naumann. 

 The method may have other applications.— On the oxidation of 

 metallic sulphides, by M. Da Clermont. — Decomposition of liquid 

 organic substances by the electric spark, with production of 

 fundamental carburets of hydrogen, by M. Truchot. — On the 

 existence of veins of bitumen in granite in the environs of 

 Clermont Ferrand, by M. Julien. — New experiments on the 

 toxical action attributed to copper and to substances containing 

 copper in combination, by M, Galippe. Tnese confirm former 

 conclusions. — Note on the first phenomena of the development 

 of sea-urchins {Echinus miliaris), by M. Giard. — M. Chasles 

 presented (from M. Riccardi) the first part of a work called La 

 Biblioteca matematica Italiana, which is to be a bibliography of 

 all Italian works on mathematics from the earliest times to the 

 beginning of the nineteenth century. 



CONTENTS Pack 



Agriculture IN THE United States 525 



Cumming's Theory of Electricitv. By Dr. Arthur Schuster . 526 



Our Hook bHKLF : — 



" Proceedings of the London Mathematical Society" 527 



Vacher's " Primer ot Chemistry, including Analysis " 527 



Letters to the Editor : — 



Hibernation of] liid-. — The DuuE of Argyll, F.R.S. .... 5:7 



The Swallows and Cuckoo at Menton. — Douglas A. Spalding . 5^8 

 Greenwich as a Meteorological Observatory.— Alexander Bu- 



chan ; John L Plummer , 5-^ 



Cast-iron —H. ?•[ 5^9 



Tycho Brahe's Portrait. — J. L. E. Dreyer 51J 



Yellow Crocuses. — Alfred George Renshaw 53,' 



Tropical Forests of Hampshire. — W. Theobald 5; 1 



Hog- Wallows or Prairie Mounds, — Prof. Joseph Le CoNTE . . ^^jj 



Our Astronomical Column : — 



Winnecke's Comet, 1877, II 531 



A New Comet 53i 



Observations at Cordoba 53 



Typical Laws of Heredity, III. By Francis Galton, F.R. S. 

 {IVzik Illustratiotis) 



Cakl Friedrich Gauss. By R. Tucker {With Illustrations) . . 5j 



MS'IEOROLOGICAL NoTES : — 



Meteorological Lustrum of 1871-75 



Distribution of Barometers in France 



Storm in the Southern and Eastern Counties 



Auroras in Canada during the Past Winter s| 



Solar Radiation in Winter and Summer 



Hail-tones in India 



The Weather of Europe 



Ball Lightning 



Notes 



Scientific Serials 



Societies and Academies S4l 



