4o8 



NATURE 



[August 23, 1888 



lamp previously standardized by a method already described by 

 one of the authors in conjunction with General Festing. In the 

 first two methods the photometer-screen was fixed, the intensity 

 of the comparison-light being adjusted by one of Varley's carbon 

 resistances ; in the third the glow-lamp was maintained at a con- 

 stant brightness, the position of the screen being adjusted along 

 a graduated photometer bar, as in the ordinary Bunsen method. 

 Full details of the construction of the several pieces of apparatus 

 are given in the original paper. 



The observations during the eclipse were made at Hog Island, 

 a small islet at the south end of Grenada, in lat. 12° o' N. and 

 lon^ 61° 43' 45" W., with the assistance of Captain Archer and 

 Lieutenants Douglas and Bairnsfather of H.M.S. Faniome. 

 The duration of totality at the place of observation was about 

 230 seconds, but measurements were possible only during 160 

 seconds, at the expiration of which time the corona was clouded 

 over. A careful discussion of the three sets of measurements 

 renders it almost certain that the corona was partially obscured 

 by haze during the last 100 seconds that it was actually visible. 

 Selecting the observations made during the first minute, which 

 are perfectly concordant, the authors obtain six measurements of 

 the photometric intensity of the coronal light at varying distances 

 from the sun's limb, from which they are able to deduce a first 

 approximation to the law which connects the intensity of the 

 light with the distance from the limb. 



The observations with the integrating apparatus made inde- 

 pendently by Lieutenants Douglas and Bairnsfather, agree very 

 closely. It appears from their measurements that the total light 

 of the corona in the 1886 eclipse was — 



Douglas 0-0123 standard candle 



Bairnsfather .... 0-0125 ,, 



Mean 



00124 



at a distance of 1 foot. 



In comparing these observations with those made during the 

 1878 eclipse, it must be remembered that the conditions of ob- 

 servation on the two occasions were widely different. The 

 observations in the West Indies were made at the sea's level, in 

 a perfectly humid atmosphere and with the sun at no greater 

 altitude than 19 . Prof. Langley, in 1878, observed from the 

 summit of Pike's Peak in the Rocky Mountains at an altitude 

 of 14,000 feet, in a relatively dry atmosphere and with the sun 

 at an altitude of 39 . 



From observations on the transmission of sunlight through 

 the earth's atmosphere (Abney, Phil. Trans., A, clxxviii (1887), 

 251) one of the authors has developed the law of the extinction 

 of light, and, by applying the necessary factors, it is found that 

 the intensity of the light during the 1886 eclipse, as observed at 

 Grenada, is almost exactly half of that of which would have 

 been transmitted from a corona of the same intrinsic brightness 

 when observed at Pike's Peak. Hence to make the observations 

 of Prof. Langley comparable with those of the authors, the 

 numbers denoting the photometric intensity of the corona in 1878 

 must be halved. The result appears, therefore, that whereas in 

 1878 the brightness of the corona was 0-0305 of a standard 

 candle at a distance of 1 foot, in 1886 it was only 0-0124 of a 

 candle at the same distance. Several of the observers of the 

 West Indian eclipse (including one of the authors) were also 

 present at the eclipse of 1878, and they concur in the opinion 

 that the darkness during the 1886 eclipse was very much greater 

 than in that of 1878. The graduations on instruments, chrono- 

 meter faces, &c, which were easily read in 1878, were barely 

 visible in 1886. In explanation of this difference in luminous 

 intensity it must not be forgotten that the 1878 eclipse was not 

 very far removed from a period of maximum disturbance, whereas 

 in 1886 we were approaching a period of minimum disturbance. 



Paris. ■ 

 Academy of Sciences, August 6. — M. Janssen, Presi- 

 dent, in the chair.— Fresh experiments on the fixation of 

 nitrogen by certain vegetable soils and plants, by M. Berthelot. 

 These researches, made with three different kinds of argil- 

 laceous soil and with plants of the leguminous family, fully 

 confirm the results of previous studies. The fundamental 

 fact that both plants and soil absorb nitrogen under the 

 most diverse conditions is now placed beyond all reasonable 

 doubt. So certain does the author consider this conclusion, 

 that he declines all further discussion on the subject of certain 

 recent negative osperiments carried out under defective condi- 



tions.— On a recent change in the views of meteorologists regard- 

 ing gyratory movements, by M. H. Faye. The author claims 

 that the new school of meteorologists, represented by Messrs. 

 Loomis, Meldrum, and Douglas Archibald (see Nature, 

 June 14, p. 149), shows a tendency to accept his conclusions on 

 certain points at issue. These authorities already admit that the 

 cyclonic movements originate, not on the surface of the earth 

 as had long been contended, but in the higher atmospheric 

 regions, a position irreconcilable witli their hypothesis of an 

 ascending, but in full accordance with M. Faye's view of a 

 descending motion. — Summary of the solar observations made 

 at the Royal Observatory of the Collegio Romano during the 

 second quarter of 1888, by M. P. Tacchini. These observations 

 show an increase of the solar spots in May and June, and of the 

 protuberances in April. The general inference is that the rela- 

 tion between these two orders of phenomena is less intimate 

 than might be supposed from previous observations.— On a new 

 apparatus for studying the friction of fluids, by M. M. Couette. 

 This method, differing from those of Coulomb and Poiseuille 

 hitherto employed, is based on the principle indicated by Dr. 

 Margules in 1881 {Wiener Berichte, 2nd series, vol. Ixxxiii. p. 

 588). It has the advantage of controlling Navier's theory for 

 very thin tubes and slow discharge, and of operating on gases at 

 constant pressure.— On levulose, by MM. E. Jungfleisch and 

 L. Grimbert. — On the malonates of potassa and soda, by M. 

 G. Massol.— On the hydrates of methane and ethylene, by M. 

 Villard. — On experimental tetanus, by M. Rietsch.— M. A. de 

 Schulten describes a process by which he has succeeded in pro- 

 ducing the crystallized anhydrous sulphates of cadmium and zinc 

 (artificial zincosite) ; and M. A. Poincare shows how are pro- 

 duced the barometric movements corresponding to the displace- 

 ment of the moon in declination. -The present number contains 

 the text of the address delivered by the President, M. Janssen, at 

 the unveiling of the monument raised by the city of Tours to 

 the memory of General Meusnier on July 29, 1S88. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED. 



Nature and the Bible : J. Davis, 2nd edition (Houlston).— Earth Know- 

 ledge Part 2 : W. J. Harrison and H. R. Wakefield (Blackie).— The Ele- 

 mentary Geometry of Conies : C. Taylor, 5th edition (Bell).— The Bacon- 

 Shakspere Question : C. Stopes (Johnson).— Curve Pictures of London : A. 

 B. MacDowall (Low).— Great Circle Sailing: R. A. Proctor (Longmans).— 

 Fifty Years of Economic Botany : J. W. Ellis— Journal of the Royal 

 Microscopical Society, August (Williams and Norgate).— Proceedings of the 

 Liverpool Geological Society, vol. v. Part 4 (Liverpool).— Brain, Part 42 

 (Macmillan).— Bulletin de l'Academie Royale des Sciences de Belgique, 

 1888, No. 7 (Brussels).— Quarterly Journal of the Geological Society, 

 August (Longmans).— MeteorologischeBeobachtungen in Deutschland, 1886 

 (Hamburg). 



CONTENTS. page 



British Petrography. By Prof. John W. Judd, 



p p o 385 



Silkworms. By W. F. Kirby ............ 3 86 



Our Book Shelf :— 



Von Fritsch : " Allgemeine Geologie 3°7 



Letters to the Editor : — 



Functionless Organs.— Prof. J. Burdon-Sanderson, 



F.R.S. ; Samuel F. Wilson 3 8 7 



Lamarckism versus Darwinism.— Edward B. Poul- 



ton ; Prof. R. Meldola, F.R.S 3» 8 



Modern Views of Electricity. IX. By Prof. Oliver J. 



Lodge, F.R.S • - • • 3»9 



A History of the August Meteors. By W. F. 



Denning - 



Notes \ 



Our Astronomical Column : — 



Comet 1888 c (Brooks) \ 



Yale College Observatory 2 



Gravitation in the Stellar Systems 39 s 



Astronomical Phenomena for the Week 1888 



August 26— September 1 3 



Geographical Notes • • • • • • ; 



The Gases of the Blood. II. By Prof. John Gray 



McKendrick, F.R.S .- • : 



Molecular Physics : an Attempt at a Comprehensive 

 Dynamical Treatment of Physical and Chemical 



Forces. I. By Prof. F. Lindemann 4 



Societies and Academies 4°7 



Books, Pamphlets, and Serials Received . . . . • 4°» 



