Nov. 25, 1886] 



NA TURE 



85 



identical with those which have been demonstrated to be the 

 cause of the fibrine disease which, in an epidemic form, from 

 1849 to 1865 ravaged the silkworm nurseries of France, and 

 reduced them to a state of ruin, but which, thanks to M. Pasteur, 

 is now practically eradicated from Europe. 



Prof. Giovanni Luvini has just issued, in pamphlet form, 

 a summary of the results of his important experiments on the 

 electric conductibility of vapours and gases. As the readers of 

 Nature are already aware, these experiments have finally 

 exploded the old theory that the moist atmosphere and other 

 vapours are good conductors. The pamphlet, which is pub- 

 lished in Florence, includes an historical survey of the subject, 

 and a full account of the processes adopted by the author. 

 Electricians are reminded that this essay, together with his 

 previous treatise on atmospheric electricity, are merely prepara- 

 tory to a comprehensive work on the phenomena connected with 

 the aurora borealis, which is now nearly completed. 



LiGHT.N'iNG-FLASHES have Sometimes been observed which, 

 starting from one point, have ended in several. Some remark- 

 able forms of flash have been lately described by Herr Leyst, of 

 Pawlowsk Observatory. In one case a flash went a certain 

 distance in a north-easterly direction, then divided, the two 

 branches forming an angle of about 75°. When these had 

 reached about 35° from each other, they turned and united again 

 to one line. The path of the lightning thus formed a quadri- 

 lateral figure. It was further observed that the lightning flashed 

 back in the same path, as if there were an oscillating discharge. 

 In another interesting fl.tsh, the path was not a crooked line but 

 a wavy band, which was lit up four times in succession with 

 equal brilliancy. The time between the second and third and 

 the third and fourth flashes seemed longer than that between 

 the first and second. The thunder which followed lasted about 

 So seconds. 



The additions to the Zoological Society's Gardens during the 

 past week include a Patas Monkey {Cercopithccus patas 9 ) from 

 West Africa, presented by Capt. T. W. Robinson ; a Puma 

 {Felis concolor i ) from El Gran Chaco, presented by Mr. Alfred 

 Grenfell, F.Z. S. ; a Malayan Bear {Ursus nialayantis) from 



Malacca, presented by Miss A. Stewart Saville ; a 



Souslik (Sfermophilus ) from California, presented by Mr. 



B. F. Russell ; a Gazelle {Gazella djrcas i ) from Barbary, pre- 

 sented by Edward J. Hough ; four Chukar Partridges {Caccabis 



chtikar) from Persia, presented by Dr. J. Huntley ; a 



Toad (Bufo ■ ■) from Africa, presented by Mr. E. N. 



Wroughton ; six Roseate Cockatoos [Cacatua roseicapilla), 

 seventeen Cockateels {Calopsitta novi^-hollandiii), six Swain- 

 son's Lorikeets (Trichoglossus novis-hollamiiic), two Red-winged 

 Parrakeets {Aprosmictus erythropterus), eight Chestnut-eared 

 Finches (Amadina castanotis), two Peaceful Doves {Geopdia 

 tranquilla) from Australia, a Nutmeg Bird (Munia punctularia), 

 two Eastern Turtle Doves (Turtiir mecna) from India, three 

 Magpie Tanagers {Cissopis len'eriana), two Red-crested Car- 

 dinals (Paroaria cucullat.i), a Red Ground-Dove (Geotrygon 

 moiilana), a Yarrell's Curassow (Crax carunculatd), a Crested 

 Curassow (Crax akclor) from South-East Brazil, two Hawfinches 

 {Coccothraiistes vulgaris), British, deposited. 



OUR ASTRONOMICAL COLUMN 



The Mass of Mercury. — In the Bulletin Astraiiomii/ut- for 

 October Herr B,acklund has published a new determination of the 

 mass of Mercury deduced from the perturbations produced in the 

 motion of Encke's comet arising from its close proximity to the 

 planet in 1878. From the apparitions of the comet in 1871, 

 1875, 1878, 1881, and 1885, Herr Backlund finds the reciprocal 



of the mass of Mercury to be 2,668,700,— thus making 

 the mass of the planet considerably larger than has been 

 found by recent investigators. .\nd Herr Backlund states that, 

 even supposing the acceleration of the comet's mean motion to 

 have been constant during the entire period 1871-85, it is not 

 possible to represent satisfactorily the five apparitions of the 

 comet during that period on the assumption that the reciprocal of 

 the mass of Mercury is greater than 5,000,000. 



The Natal Observatory. — Mr. Nelson has issued his 

 Report, as Superintendent of the Natal Observatory, for the 

 year 1885. The staff of the Observatory consists of the 

 Government Astronomer, an Astronomical Assistant, and a 

 Meteorological Assistant. Four ladies have also been employed 

 during the year as astronomical computers. The equatorial 

 appears to have been but little used in 1885, all the astronomical 

 observations recorded having been made with the 3-inch transit. 

 The total number of observations made with this instrument was 

 706, including transits of stars, of the sun, of the moon's linib, 

 of the lunar crater Murchison A, and observations of zenith 

 stars for latitude. With regard to the latter class of observa- 

 tions, it is proposed to determine the latitude of the Observatory 

 with the greatest care, as one of the primary points of the geo- 

 detic triangulation of South Africa. Forty pairs of stars have 

 been selected for this purpose, mostly differing in zenith distance 

 by not more than 3' or 4'. Also, with the view of better con- 

 necting the fundamental declinations of the star catalogues of 

 northern and southern observatories, arrangements have been 

 made for comparing, by Talcott's method, the zenith distances 

 of a number of southern circumpolar stars with suitably placed 

 northern stars of corresponding zenith distance. A list of thirty- 

 two stars has been prepared for this purpose. Mr. Neison also 

 reports on the state of his own work on the lunar theory, which 

 he appears to consider of an official character. 



Comet Finlay (18S6 e).—The following ephemeris of this 

 object is by Dr. A. Krueger [Astr. Nachr., No. 2755) : — 



For Berlin Midnight 

 R,A. Decl. log '. 



Bright- 



Nov. 28 21 o 50 19 107 S. 9"994i 9'9i42 3'° 



30 21 10 58 18 204 



Dec. 2 21 21 12 17 27-2 9'997i 99060 3-1 



4 21 31 30 16 3fo 



6 21 41 53 15 31-9 00016 9S992 3-1 



8 21 52 20 14 300 



10 22 2 49 13 25-6 S. 0-0074 9'894' 3'i 

 The brightness at date of discovery is taken as unity. 



Comet Barnard {1886/).— The following ephemeris of this 

 object for Berlin midnight is by Dr. Oppenheim (Dun Edit 

 Circular, No. 130) : — 



18B6 R-A. Decl. log r log .i Brigllt- 



h. m. s. . , ness 



Nov. 27 14 34 10 16 5o'4 N. o'oo29 98864 17-8 



29 14 54 42 17 23-5 



Dec. 1 15 16 12 17 460 9'9S79 9-8640 21-2 



3 15 38 23 17 560 



5 16 o 54 17 51-8 9'9839 9'8448 23-6 



7 16 23 24 17 33-0 



9 16 45 27 17 o-i N. 9-9920 9 8303 24-3 

 The brightness at date of discovery is taken as unity. 

 Gore's Nova Oeionis. — It seems to be clearly established 



that this interesting star is indeed— as was from the first sus- 

 pected from the character of its spectrum — a simple variable, 

 and not one of the class to which the title " temporary " can be 

 fitly applied. M. Duner, who had observed the star at intervals 

 from last December to the end of April, ioun&iAslr. Nachr., 

 No. 2755), on renewing his observations at the end of October 

 and the beginning of the present month, that it had unmistakably 

 increased in brightness in the interval, and was continuing to do 

 so. Herr Fr. Schwab and Mr. Espin confirm this conclusion, 

 the former having observed this star early in last July, and found 

 it then fainter than the 12th magnitude. Its period would 

 appear to be not far from one year ; Herr Schwab gives it as 

 one or two weeks longer than a year, and as ranging in bright- 

 ness from 6m. to I2im., whilst M. Duner assigns a period of 

 359-5d. to it. It is clearly of importance that it should be care- 

 fully watched during the coming winter. 



