9 6 



NA TURE 



[May 24, 1883 



which passed ever into a negative polarisation with the longer 

 duration of the primary current. Here also the different mani- 

 festations of the nerve polarisation led, as in muscles, to the 

 recognition of two simultaneous electromotive forces, which 

 behave differently to the intensity and duration of the primary 

 current. And as in uin cle the direction of the primary current 

 influenced the strength of the positive polarisation, similarly in 

 nerves the direction had an influence upon the positive polarisa- 

 tion predominating' in the motor nerve-roots when the current 

 was a descending one, and conversely in the sensory nerve-roots 

 when the current was an ascending one ; consequently both times 

 the direction of the physiological nerve-wave predominated. 

 Finally, Prof, du Bois Keynwnd gave an account of his experi- 

 ments by wh ch he has demonstrated quite analogous secondary 

 electromotor phenomena in the electric organs of the electric 

 fish (Malapterurus). In the theoretical di cussion of the results 

 of these experiments that were carried on for so many years the 

 lecturer pointed out in conclusion that the inner polarisation, 

 the positive polarisation in particular, could scarcely be other- 

 wise explained except by the hypothesis that in the above- 

 mentioned organs (the muscles, nerves, and electric organs) 

 electromotor molecules preexisted during life, which, being turned 

 by the polarising current, became the occasioned causes of the 

 electromotor phenomena. — I'rof. Rosenthal of lirlangen spoke 

 about the experiments he had made to ascertain the electric con- 

 ductivity of living tissues. He dwelt on the difficulty of exactly 

 measuring its amount, which he could only overcome by using 

 alternating currents, of which, by the help of a particular appar- 

 atus, currents of one direction only acted upon the galvanometer 

 of the Wheatstone's bridge. On the living man he found the 

 resistance of the epidermis so great that he regards it as an 

 excellent insulator which permits the electrical current to pa s 

 through to the deeper organs only thr iugh the medium of the 

 canals (the pores) that ramify through it and that are filled 

 with fluid. The measurements of the c mductivity of living 

 animal tissues are not yet quite completed. 



Paris 



Academy of Sciences, May 7. — M. Blanchard in the chair. 

 — M. Loewy explained his new method for determining at any 

 moment the relative position of the instrumental equator in 

 relation to the real equator. This method is analogous to that 

 already given fir right ascensions, being founded on the obser- 

 vation of the stars near the pole, and on the variations in the 

 relations of the coordinates due to the deflection of the instru- 

 ment. M. Loewy demonstrates mathematically that his plan 

 combines all the theoretical and practical conditions required for 

 the complete solution of the problem. It is based on the theorem 

 here demonstrated that when the track described by a star in 

 apparent distance from the pole coincides with its distance in 

 relation to the instrumental plane, the angle may be exactly 

 determined which is formed by the terrestrial axis with the line 

 of the instrumental poles, by means of the variation observed 

 between the apparent polar (list nee and the distance in relation 

 to the instrumental plane. The method is independent of any 

 possible variations in the state of the instrument during a period 

 of twelve hours, and it excludes the cause of systematic error 

 due to refraction. It is moreover capable of extreme accuracy, 

 which, by multiplying the points, may be carried as far as is 

 des'rable. — M. Tresca submitted some remarks on the observa- 

 tions made last year by Prof. Lemstrom in Lapland on various 

 circumstances connected with the phenomenon of the aurora 

 borealis, which have been reported in Nature. — M. Th. 

 du Moncel presented a paper by M. E. Semmola on the 

 annual variation of temperature in the waters of the Bay of 

 Maples, showing the results of observations made during the 

 .summer of 1879 and January, 1880, with a Negretti and 

 Zambra thermometer. The observations were generally taken 

 during calm weather between the hours of 11 a.m. and 3 

 p.m., in depths of 30 or 40 feet, and at some distance from 

 the coast. They showed that on the whole the Bay of Naples 

 is only a few degrees warmer than the Mediterranean, which, 

 from the observations made in the August of 1870 by the 

 English expedition under Prof. Carpenter, was found to be 25° C. 

 at the surface, I5°'5 at a depth of 180 feet, 14 at 230, 13 at 

 620, and nearly the same down to 10,000 feet. In the bay the 

 temperature varied from 13 on the surface in winter to 27° in 

 summer, showing a mean of about 20°, or 3° higher than the 

 city of Naples. This result also agrees with the mean annual 

 temperature of the Mediterranean, which, according to Mohn, 



lies between 16° and 19' in the west, and.2t°-23° in the east. — 

 Other papers were c intributed by M. Lecoq de Boisbaudran 

 on the extremely sensitive character of salts of iridium, 

 rendering them most useful in detecting the presence of 

 the smallest particles of iridium in compound substances; 

 by G. A. Hirn, continuing the risuml of the meteoro- 

 logical observations made during 1882 at four points of the 

 Upper Rhine and Vosges highlands; by Th. Sehwedoff, on 

 the form of the great comet of September, 1882, with two cuts 

 shoeing its appearance on October 12 at Lyons, and on October 

 17 and Novemter 7 at Odessa; by E. de Jonquieres, on the 

 identities presented by the reductions belonging respectively to 

 the two "modes " of continuous periodical fractions. By " the 

 two modes" of continuous fractions the author understands, on 

 the one hand the ordinary continuous fractions (" first mode "), 

 on the other those in which the numerators differ from unity 

 ("second mode"). — Papers were also submitted by M. Vieille, 

 on the specific heats of some gases at high temperatures ; by C. 

 Rcsio, on the electrodynamograph, an instrument constructed 

 for recording the work executed by machinery ; by J. A. Le Bel, 

 on the amylic alcohol developed in alcoholic fermentation ; by 

 M. Gonnard, on the staurolites and regular groupings of the 

 felspar crystals in the siliceous porphyry of Four-la Brouque, 

 near Issnire (Puy-de-Dome) ; by J. Thoulet, on the elasticity of 

 rocks and minerals ; by P. Megnin, on the direct reproduction 

 of tcenia in the intestines of the dog and man ; by B. de Chan- 

 courtois, on a common meridian and measurement of time in 

 view of the universal adoption of a compl te decimal system, 

 with a planisphere showing two proposed initial meridians 

 passing through Behring Strait and the Azores ; by Ch. Conte- 

 jean, on some special cases of distribution in the Italian flora. 



CONTENTS Pace 



Science and Art 73 



The Living Organisms of the Atmosphere. By 



Henry de Varigny 76 



Animal Technology 77 



Our Book Shelf:— 



Toth's "Minerals of Hungary, with Special Regard 



to the Determination of their Occurrences "... 78 

 Letters to the Editor : — 



Natural Selection and Natural Theology. — Prof. Asa 



Gray 78 



The Fauna and Flora of the Keeling Islands, Indian 



Ocean. — Henry O. Forbes 78 



"Festooned" or " Pocky " Clouds (Mammato-Cumu- 



lus). — Hon. Ralph Abercromby (With Diagram) 70 



The Sacred Tree of Kum-hum. — E. L. Layard . . 79 



Sheet-Lightning. — The Reviewer 80 



Solar Halo.— Thos. Ward ; Sm 80 



Mock Moons. — T. W. Backhouse 81 



Helix pomatia. — W. C. Atkinson 8t 



Cape Bees. — M. Carey-Hobson 81 



The Effect of the Change of Colour in the Flowers ot 

 " Pulmonaria officinalis " upon its Fertilisers. — Dr. 



Hermann Miiller 81 



The Soaring of Birds. — James Currie 82 



Intelligence in a Dog. — Prof. Francis E. Nipher . 82 



Mid-height of Sea Waves. — W. Parfitt 82 



A Curious Survival 82 



The Poisonous Lizard 83 



Cn the Condensation of Vapour from the Fumaroles 

 of the Solfatara of Pozzuoli. By Dr. Italo 



Giglioli 83 



State of the Atmosphere which produces the Forms 

 of Mirage observed by Vince and by Scoresby. By 



Prof. P. G. Tait ( With Diagrams) 84 



Notes 88 



Our Astronomical Column : — 



The Comet of 1707 89 



The Transit of Venus 90 



The British Association Catalogue of Stars .... 90 



Geographical Notes 90 



Electrical Units of Measurement. By Sir William 



Thomson, F.R.SS.L. and E., M Inst. C.E. ... 91 



U.S. National Academy of Sciences 92 



Scientific Serials 93 



Societies and Academies 93 



