6o8 



NATURE 



[October 22, 1891 



SOCIETIES AND ACADEMIES. 

 Paris. 

 Academy of Sciences, October 12.— M. Duchartre in the 

 chair. — On the theory of the antagonism of visual fields, by 

 M. A. Chauveau. — An apparatus for carrying out various ex- 

 periments connected with the study of binocular contrast, by the 

 same author. The instrument described is that used by M, 

 Chauveau in the experiments the results of which were com- 

 municated to the Academy on September 7 and 21. In the 

 main it consists of a stereoscope having arrangements by means 

 of which exact equality of luminous impressions may be realized, 

 and the colours of the two fields altered independently. — New 

 reseau of isotherms for carbonic acid, by M. E. H. Amagat. 

 The author has determined the isotherms of carbonic acid for 

 every 10° from 0° to 100°, and also those corresponding to 32°, 

 35^ I37°» 198°, and 258° ; the pressures having been taken up to 

 1000 atmospheres. The results obtained are graphically shown 

 in the accompanying figure, in which the abscissae represent 

 pressures, and products of P X V furnish the ordinates. — Vai iation 



of the composition of Jerusalem artichokes at different periods of 

 their growth ; rSle of the leaves, by M. G. Lechartier. Analyses 

 of the dried black leaves which appear on Jerusalem artichokes 

 in the autumn have been made, and the results compared with 

 analyses of green and yellow leaves. The effect of different 

 fertilizers on their composition has also been studied. It appears 

 that the black leaves must have had the same composition as the 

 green leaves, and the substances which they lose are utilized for 

 the nutrition of the higher leaves of the plants. They preserve 

 their vitality as long as the soil furnishes the plant with sufficient 

 phosphoric acid and potash. But if either of these fertilizers be 

 absent, the leaves begin to dry up.— Observations of Tempel- 

 Swift's periodic comet, made at Paris Observatory with the 

 West Tower equatorial, by M. G. Bigourdan. Observations 

 for position were made on October 8 and 9. It is remarked : 

 " The comet is an excessively feeble nebulosity, at the extreme 

 limit of visibility: it is round, from i'"5 to 2' in diameter, and 

 slightly brighter towards the centre." — Observations of the same 

 comet, made at Paris Observatory with the East Tower 

 equatorial, by Mdlle. D. Klumpke. An observation for 

 position was made on October 9.— Experimental researches 

 on "personal equation" in transit observations, by M. P. 

 Stroovant. The author has determined his " personal equa- 



No. II 47, VOL. 44] 



tion " for observations of stellar points and disks under different 

 conditions of illumination of the field of the telescope em- 

 ployed. Ilis equation was very different when the preceding 

 edge was observed to transit than when the passage of the follow- 

 ing edge was noted. It was also subject to a slight variation. 

 Observations by the " eye and ear method " show a tendency to 

 choose certain tenths of a second in preference to others. — On 

 conjugate systems and on the deformation of surfaces, by M. E, 

 Cosserat. — On turbo-machines, by M. Rateau. — Variation of 

 the electromotive force of piles with pressure, by M. Henri 



Gilbault. Taking the formula <7 — =z dv, in which E = elec- 



dp 

 tromotive force, q the quantity of electricity developed and 

 producing a varia'ion of volume v, and / the pressure, the 

 author has calculated the variations of the electromotive force of 

 different piles, and finds that the results agree extremely well 

 with those arrived at experimentally up to a pressure of 100 

 atmospheres. — A multitubular electric accumulator, by M. D. 

 Tommasi. — Calculation of the specific heats of liquids, by M. 

 G. Hinrichs. — Melting-point of certain binary organic systems, 

 by M. Leo Vignon. — Calorimetric researches on the state of 

 silicium and aluminium in cast-irons, by M. F. Osmond, — Heat 

 of formation of platinic bromide and of its principal compounds, 

 by M. Leon Pigeon. — Contribution to the study of hemato- 

 zoaires ; on the hematozoaires of the frog, by M. Alphonse 

 L-abbe. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED. 



The Life-Romance of an Algebraist : G. W. Pierce (Boston, Cupples). — 

 Blackie's Science Readers, III. (Blackie).— Recenti Progress! nelle Applica- 

 zioni deir Elettricita ; Parte Prima, Delle Dinamo : Prof. R. Ferrini (Milano, 

 Hoepli). — A Manual of l^ogic : J. VVelton, vol. i. (Clive). — Text-book of Com- 

 parative Anatomy : Dr. A. Lang ; translated by H. M. and M. Bernard . 

 Part I (Macmillan).— Photography Applied to the Microscope : F. W. Mills 

 (Iliffe).— Photographic Pastimes: H. Schnauss, translated (Iliffe).— Handy 

 List of Books on Mining : H. E. Haferkora (Gay and Bird) — A Treatise 

 on Nitrogen (J. Heywood).— A Contribution to the History of Rain-Gauges : 

 G. J. Symons.— The Constitutional Development of Japan, 1853-81: T. 

 I venaga (Baltimore). — Praktrsches Taschenbuch der Photographie : Dr. E. 

 Vogel (Berlin, Oppenheim). — Bulletin of the American Geographical Society, 

 vol. xxiii. No. 3 (New York). — Encyklopaedie der Naturwissenschaften, 65 



and 66 Liefg. (Williams and Norgate). 



CONTENTS. PAGE 



Rudolf Virchow and his Countrymen . 585 



Electric Light Fitting— Good and Bad Work ... 586 



More Suggestions for County Councils 588 



The Missouri Botanical Garden. By E. G. B. . . . 588 

 Our Book Shelf:— 



Ball: " The Story of the Heavens ■' 589 



Martin : " Notes on Elementary Physiography "... 589 

 Richardson : " Thomas Sopwith, M.A., C.E., 



F.R.S." 590 



Letters to the Editor : — 



Electric Transmission of Power. — ^Joseph John 



Murphy ; W. E. A 590 



Rain-making. — Dr. Italo Giglioli 590 



Weather Cycles and Severe Winters. — A. B. M. . . 591 



A Lunar Rainbow. — Dr. P. Q. Keegan 591 



The Destruction of Mosquitoes. — S. A. M 591 



Law of Tensions. — H.G.Williams 591 



The Koh-i-Nur: a Reply.— V. Ball, F.R.S. ... 592 



The Nautical Almanac 593 



Rain-making in Texas. By Prof. George E. Curtis 594 

 Colour-blindness generally Considered. By T. H. 



Bickerton .... 595 



On Van der Waals's Treatment of Laplace's 

 Pressure in the Virial Equation : a Letter to 



Prof. Tait. By Lord Ray leigh, F.R.S 597 



Notes 597 



Our Astronomical Column: — 



Distribution of Lunar Heat 601 



Geological Society of America 601 



Technical Chemistry, By Prof. R. Meldola, F.R.S. 602 

 An Astronomer's Work in a Modern Observatory. 



By Dr. David Gill, F.R.S 603 



Societies and Academies .... 608 



Books, Pamphlets, and Serials Received 608 



