48o 



NATURE 



[April I s, 1875 



cannot be seen with equal distinctness witliout adjusting the 

 focussing glass. A black patch of paper on a blue ground 

 appears to have a fringed edge if viewed from even a shoit dis- 

 tance, while a black patch on a red ground, when observed 

 under similar conditions, has a perfectly distinct margin. _ Prof. 

 M'Leod then explained that the overlapping of images in the 

 eye produced the mental impression that there is no want of 

 achromatism. It is interesting to note that WoUaslon coiisidered 

 that the coloured bands of the spectrum were really divided by 

 the black (Fraunhofer) lines, and his statement that the 

 red end of tiie spectrum does not appear to have a boundary 

 line, "because the eye is not competent to converge the 

 red rays properly," shows that he had very nearly, if not 

 quite, discovered the achromatic defects of the eye. Dr. 

 Young ascribes to WoUaston the merit of having observed 

 that when a luminous point is viewed through a prism the blue 

 end appears to be wider than the red, the eye being incapable of 

 recognising that the spectrum has the same width throughout its 

 entire length. An excellent experiment was then exhibited to 

 show the relative distinctness of a dark line on grounds of various 

 colours. A string or wire was so arranged that its shadow tra- 

 versed the entire length of a spectrum which was thrown on a 

 screen by an electric lamp. When viewed from a short distance 

 the edges of the shadow appeared to be sharp at the red end, 

 but gradually became less distinct, until at the blue end nothing 

 but a blurred line remained. Dr. W. II. Stone considered that 

 the paper was specially valuable as suggesting a possible mode 

 of investigating the relation between the defects in the eye and 

 the personal co-eflicient of error in observation. — Prof Guthrie 

 showed a kaleidoscope, devised by Mr. R. Cowper, in which the 

 usual geometrical effects were produced by fragments of mica 

 illuminated by polarised light. — Mr. Wilson, Demonstrator in 

 the Physical Laboratory, South Kensington, exhibited a modifi- 

 cation of Thomson's galvanometer, which might be readily con- 

 structed at a small expense. Pie used two discs of glass and 

 replaced the usual brass quadrants by tinfoil ; the connection 

 between the binding screws and the quadrants was effected by 

 fusible solder and platinum wires. — The Vice-President then 

 alluded to the lamented death of Mr. C. Becker, of the firm of 

 Messrs. Elliott, whose loss will be severely felt in every laboratory 

 in this country. 



Royal Microscopical Society, April 7. — II. C. Sorby, 

 F.R.S., president, in the chair. — A paper by the Rev. W. H. 

 DaUinger and Dr. Drysdale was taken as read ; it was entitled, 

 " Some further Researches upon the Lile History of the 

 Monads," and described the results of a number of careful 

 observations made in continuance of the series communicated 

 upon former occasions. — The President read a paper on some 

 contrivances for the study of spectra and for applying the mode 

 of spectrum analysis to the microscope. Having exhibited and 

 e-xplained the improved form of spectrum microscope, the adapta- 

 tion of the spectioscope to the binocular arrangement, and a new 

 form of diaphragm, the author proceeded to show the meaning 

 of the absorption bands and the various methods of measure- 

 ment and determination, pointing out the advantages of his new 

 wave-length s) stem over his former plan of comparison with the 

 quartz interference scale. The effects of acid or alkaline addi- 

 tions to solutions were also 3own by means of diagrams. 



Institution of Civil Engineers, April 6. — Mr. Thos. E. 

 Harrison, president, in the chair. — The first paper read was 

 on the manufacture of steel, by Mr. Wm. Hackney, B.Sc. — The 

 second paper was on Bessemer sttel rails, by Mr. Josiah Timmis 

 Smith. The object of this paper was to endeavour, briefly, to 

 show that, with care in manipulation and in selection of mate- 

 rials, Bessemer steel might be produced constant in quality, and 

 that certain inexpensive tests might be applied which would abso- 

 lutely determine the quality of the material, in most if not all of 

 its characters, so far as was required for railway and structural 

 purposes. 



Paris 



Academy of Sciences, April S-— M. Fremy in the chair.— 

 The following papers were read : — On a singular case of mag. 

 netisation, by 1\I. J. Jamin. — On the theory of aspiration, with 

 remarks on the new note of M. Peshn, by M. Faye. — On the 

 Jimits of combining carbon with iron, by M. Boussingault. — On 

 some documents relating to the history of diabetes, by M. 

 Andral. — M. van Beneden then presented to the Academy a 

 work on parasites in the animal kingdom. — The Academy then 

 nominated a number of gentlemen to superintend the competi- 



tion for various prizes during 1875. — On a scientific balloon ascent 

 of long duration, by MM. Sivel, Croce-Spinelli, A. and G. 

 Tissandier, and Jobert. This is a detailed account, with several 

 diagrams, of the ascent made by these gentlemen in the balloon 

 Le Zenith on March 23rd last. The balloon was 18 metres in 

 diameter, and held 3,000 cubic metres of gas ; the scientific 

 obsen'ations were made with barometers, thermometers, hygro- 

 meters, compasses, telescopes, and spectroscopes. Moreover, 

 they had a fine electroscope, with a long copper wire of 200 

 metres, and an apparatus to measure the absorption of carbonic 

 acid. The observers saw a fine lunar halo and six shooting stars, 

 one of which with a long intensely blue trail. Four carrier 

 pigeons were despatched, none of which returned to Paris. — A 

 note by M. Sirodot, on the Mammoth of Mont-Dol (Ille-et- 

 Vilaine). — On the relation between the in cyclic periods of the 

 exponent of an algebraic curve of the nt degree, by M. Max 

 Marie. — Researches on co-variables, by M. C. Jordan. — A 

 memoir by M. II. Durrande, on the applications of the 

 general theories of dynamics to the motions of a body of 

 varying form. — A note by M. Bouty, on the quantities of mag- 

 netism and the situation of the magnetic poles in thin needles. — 

 On the physical properties of thin layers of collodion, by M. E. 

 Gripon. — On the formation of iodic acid in flames in which iodine 

 is volatilised, by M. G. Salet. — A note by M. R. Engel, on the 

 substitution of hydrogen by mercury in creatine. — A note by 

 by M. Lecoq de BoLsbaudran, on the inequality of action of dif- 

 ferent isomorphous bodies on the same supersaturated solution ; 

 account of experiments made principally with potassic chrome 

 alum and ammonia alum. — On a new process of extracting salt 

 from soils, applied in the South of Fiance, by M. A. Joannon. 

 This process renders large tracts of land, which are now lying 

 bare and unfertile, fit for purposes of agriculture. — A note by 

 M. A. F. Marion, on the anatomy of a remarkable species of the 

 group of Nemertida, Drcpanophoncs sprctabilis. — A note by M. 

 E. Prillieux, on tumours produced on the wood of apple-trees 

 by the Piiccron lani«ire (a parasitic insect). — A note by M. 

 Dezautiere, on the sounds produced by the heart. — MM. Schnetz- 

 ler, I'elletrau, Chase, Nodey, Chaperon, and Delfau, then made 

 some communications with regard to Phylloxera. — M. Petrequin 

 then addressed to the Academy several papers on the application 

 of galvano-puncture in the treatment of aneurisms. — A memoir 

 by M. Jacquet, on the use of the tables of Pythagoras for any 

 number. — A note by M. Tridon, on the means of making 

 telescopic observations and obtaining photographic proofs 

 in the inside of an aerostatic diving-bell. — A note by M. Gruey, 

 on the zodiacal light observed at Toulouse in February and 

 March 1S75, giving detailed tables of the observations of this 

 interesting phenomenon. — On a method of calculating the abso- 

 lute perturbations of comets, by M. Hugo Gylden. — On manga- 

 nesiferous iron from carbonates, by MM. L. Troost and P. 

 Hautefeuille. — Researches on the carbon of white cast-iron, by 

 M. P. Schiitzenberger and A. Bourgeois. — On the theory of 

 storms, a reply to M. Faye, by M. H. Peslin. — A note by M. 

 Hildebrand Hildebrandsson, on the superior currents of the 

 atmosphere in their relation to the isobarometrical lines. — On a 

 new formula for the calculation of the refractive power (or the 

 number) of convex lenses, by M. Monoyer. — Gen. Morin then 

 presented to the Academy a new part of the Rr^ue d' Arlilleric, 

 published by order of the War Minister. 



CONTENTS Pack 



RovAL Agricultural Society's Journal, I. " 401 



Cooke's " Fungi" 462 



MM. H. AND E. Milne-Edwards's New WoRi^ ON RIam.mals . . 463 

 UUR Book Shelf: — 



Turner's *' Human Anatomy " 464 



Letters to the Editor: — 



On the " Law of Fatigue " regulating Muscular Exertion. — Prof. 



Samuel Haughton, F.R.S. (JK/^/, ///,/i/r,j/i<;Kj) 464 



a'he"Woir"inthe Violoncello.— W. H.Stone 466 



Flowering of the Hazel. — ,\. \V. Bennett, F.LS 466 



A Flint Cell.— E. J. .VCoURT Smith 4^6 



Arctic Temperatures.— Joseph John Murphy 467 



Aeronautics. By W. de Fonvielle 467 



Arctic Geology, I L By C. E. De Rance, F.G S 467 



The Progress OF the Telegraph, III. (H/.-/i///«s.v<,/w,M ). . . 470 

 Our Astronomical Column : — 



The Solar Eclipse of igco. May 28 472 



Winnecke's Comet 473 



The Star B. A C. 269s 473 



The "Times" Weather Chart (;F;//i///i.'j/r«//OT() 473 



The Eclipse Expedition 474, 



Notes 474 



Accidental Explosions, IL By Prof. F. A. Abel, F.K.S. ... 477 



Societies and Academies ■. . e . 478 



