20 



NATURE 



[Nov. 6, 1873 



result of a conference at the Jardin d'Acclimatation in July, and 

 appears opportunely at the jiresent moment, when the suliject is 

 attracting so much public attention, — M. E. Ferris continues his 

 remarks on "Birds and Insects." 



SOCIETIES AND ACADEMIES 

 Manchester 

 Literary and Philosophical Society, October 7. — E. W. 

 Binney, vice-president, in the chair. — "Atmospheric Refraction 

 and the last rays of the Settnig Sun," by Mr. D. Winstanlej'. It is 

 recorded in the Proceedings of this Society that a letter dated 

 from Southport and written by Dr. Joule was read at the meeting 

 held on the 5th October, 1S69. In that letter it is remarked that 

 "Mr. Baxendell noticed the fact that at the moment of the 

 departure of the sun below the horizon the last glimpse is 

 coloured bluish green." Dr. Joule also observes that on two or 

 thrrc occasions he had himself noticed the plienomenon in 

 que" ion, and that "just at the upper edge where bands of the 

 sun's disc are separated one after the other by refraction, each 

 band becomes coloured blue just before it vanishes." During 

 the past eighteen months the writer, from his residence in Black- 

 pool, has liad frequent Ojiportunities of observing the setting 

 sun, and has noticed the phenomenon of the final coloured ray 

 certainly more than fifly times. To the naked eye its appearance 

 has generally been that of a green spark of large size and great 

 intensity, very similar to one of the effects seen when the sun 

 shines upon a well-cut diamond. The colour, however, is by no 

 means constant, being often, as in the case of Mr. Ba.\endeU's 

 observation, bluish green, and at times, as mentioned by Dr. 

 Joule, quite blue. The period of its duration, too, is likewise 

 variable. Sometimes it lasts but half a second, ordinarily per- 

 haps a second and a quarter, and occasionally as much as two 

 seconds and a half When examined with the assistance of a 

 telescope, it becomes evident that the green ray results at a 

 certam stage of the solar obscuration, for it begins at the points 

 or cusps of the visible segment of the sun, and when the " set- 

 ting " is nearly complete, extends from both cusps to the central 

 space between, where it produces the momentary and intense 

 spark of coloured light visible to the unaided eye. From the 

 fact of the green cusps being rounded I apprehend that irra- 

 diation contributes to the apparent magnitude of \\ hat is seen. 

 The range of colour too as seen in the telescope is more 

 varied, and the duration of the whole plienomenon more ex- 

 tended, than when the observation is made only with the naked 

 eye. Respecting the increased range of colours seen when the 

 phenomenon is oljserved A\ith telescopic aid, I may mention that 

 on the 2Sth of June the sea was calm and the sky quite cloudless 

 at the setting of the sun. Of the final coloured rays fifteen 

 diameters showed the first to be a full and splendid yellow, 

 which was speedily followed by the usual green, and then for a 

 second and a half by a full and perfect blue. Respecting the 

 increased duration of the colour, I have found that when the 

 atmosphere is sufficiently favourable to allow a power of sixty 

 diameters being enrployed with a three-inch object-glass, the 

 green effect is seen at that part of the sun's limb in contact with 

 the horizon even when one half the sun is still unset, and of 

 course from then till final disappearance. The different colours 

 seen, together with the order of their appearance, are suggestive 

 of the prismatic action of the atmosphere as the cause of their 

 production, and the interception of the horizon or the cloud as 

 the cause of their separation. Assuming the correctness of this 

 view, it becomes evident that an artificial horizon would prove 

 equally efficaciuus in separating the coloured bands, and also 

 tliat if employed during an inspection of the sun's lower limb, 

 the least refrangible end of the spectrum would be disclosed. 

 By projecting a large image of the sun into a darkened room I 

 was enabled to get the whole of the spectrum produced by the 

 prismatic action of the atmosphere in a very satisfactory manner. 

 In this case a semicircular d'aphram was used, so placed that its 

 straight edge divided the field of view into equal parts, from 

 one of which it obscured the light. The diaphrani was placed 

 in the focus of the eyepiece, and by rotating it every portion of 

 the sun's limb could be in turn examined, and that too in the 

 centre of the field, so as to be equally subjected to the minimum 

 of the peculiarities of the instrument. When the sun's lower 

 limb was allowed to descend into the field of view the first rays 

 were intensely red. After a momentary duration they gave place 

 in succession to orange, yellow, and green, which were then lost 



in the ordinary refulgence of the sun. The upper limb gave 

 green, blue, and finally purple, which latter colour I have thus 

 far never seen upon the natural horizon. I apprehend that the 

 results here given sufficiently prove that atmospheric refraction is 

 the cause of the coloured rays seen at the moment of the sun's 

 departure below the horizon. 



Cambridge Philosophical Society, Oct. 20. — The follow- 

 ing communications were made to the Society : — By Mr. J. C. W. 

 Eliis, .Sydney College : Mechanical means for obtaining the real 

 roots of algebraical equations. — By Mr. A. Marshall, St. John's: 

 Graphic representation by aid of a series of hyperbolas of some 

 economic problems having reference to monopolies. — By Mr. H. 

 H. Cunyngame, St. John's : A machine for constructing a series 

 of rectangular hyperbolas with the same asymptotes. 

 Paris 



Academy of Sciences, October 27. — M. de Quatrefages, 

 president, in the chair. — The following papers were read : — 

 Sixth note on guano, by M. Chevreul. — Answer to Respighi's 

 note on the magnitude and variation of the sun's diameter, by 

 Father Secchi. The author defended his method from Respighi's 

 criticisms as regards the effect of heat in distorting the image 

 during the passage through the prisms. He found that the efiect of 

 heat on compound prisms was very considerable, and therefore 

 used his object-glass prism ; and stated that in a future letter he 

 intended to show that there were true variations in the solar 

 diameter. — On crystalline dissociation, by MM. Favre and 

 Valson. The authors continued the account of their re- 

 searches, the present portion of the paper dealing with the 

 valuation of the work done in the various solutions. — Note on 

 the tertiary supra-nummulitic formation of the Carcassone basin, 

 by M. Leymerie. — On certain cases of human double monstro- 

 city, by M. Roulin. — Note on the origin and method of 

 development of omphalosic monsters, by M. C. Dareste. — 

 New method of condensing liquifiable substances held in suspen- 

 sion by gases, a reply to M. Colladon, by M.\I. E. Pelouze and 

 P. Audouin. — M. Gue'rin-Me.ieville sent a letter in which he 

 asserted that the Phylloxera is not the cause, but a consequence 

 of the vine disease. — Note on the swellings produced on vine 

 rootlets by the Phylloxera, by M. Max. Cornu. — Results of ex- 

 periments on the destruction of the Phylloxera by means of 

 carbonic disulphide, by M. Bazille. The author found that this 

 agent was very successful, and that the doses could be reduced 

 considerably but that different soils require different doses. — On 

 the action of the condenser on induction currents, by M. Lecocq 

 de Boisbaudran. — On the purification of hydrogen, by M. Ch. 

 Viollette. — On the Cape diamond fields, by M. liugon — On 

 the sugar contained in vine-leaves, by M. A. Petit. The author 

 found in i kilo of leaves as much as 33 grammes of cane sugar 

 and 12 of glucose ; this was, however, exceptional, the latter 

 generally exceeding the former and the total quantity of both 

 being less. — On the Rhizocephalous Cirripedes, by M. A. Giard. — 

 On the irritability of stamens, by M. E. Heckel. The author 

 has distinguished two orders of movement in these organs. 



CONTENTS Page 



The Government and our National Museums i 



Bain's Review OF " Darwin ON Expression" 2 



Lahore TO Yakkand 3 



Our Book Shelf 4 



Letters to the Editor : — 



Prof. Youngand the Presence of Ruthenium in the Chromospfiere. 



—Prof. H. E. Roscoe, F.R.S 5 



Tlie Miller- Cas-jll.i Tliermometer. — P. Pastorhlli 5 



Captain Hutton's "Rallus Modestus." — Dr. Walter L Buller . 5 



Flight of Birds —Prof Joseph Le Conte 5 



Collective Instinct— George J. Romanes : Dr. A. Paladilhe . s 



Venomous Caterpillars. — R. McLachlan, F.L.S 6 



Harmonic Echoes. — Arnulph Mallock 6 



Evolution as applied to the Chemical Elements.— C. T. Blanshard 6 



Ancient Balances.-G. F. Rodwell, F.C.S 8 



Brilliant Meteors.— John Curry 8 



Sir Henry Holland 8 



The American Museum of Natural History in Central Park. 



New York. By Albert L. Bickmore, Ph. D g 



The Common Frog, III. By St. George Mivart. F.R.S. («'i//i 



llhtstratiotis) ' . . 10 



A Fossil Sirenian from the Red Crag OF Suffolk 13 



On the Stick-Fish {Osleocella septentrimaUs) and on the Habits 



OF Sea-Pens. By Dr. J. E. Gray. F.R.S i. 



The Relation of Man to the Ice-Sheet in the North of 



England. By R. H. Tiddemann, F.G.S 14 



Atlantic Fauna. By Fred. P. Johnson 15 



Notes 16 



The Selection and Nomenclature of Dynamical and Elec- 

 trical Units 18 



Scientific Serials . , 19 



Societies and Academies 20 



