328 



NA TURE 



[Fed. 4, 1886 



might be considered as a mere variety), and the Phoxnius 

 poljakowi, which is nearly akin to tlie Ph. locvis of the Obi and 

 North- East Europe. From these facts M. Nikolsky conchides 

 that if a direct communication between Lake Balkash and Lake 

 Aral has ever existed— that is, if a marine basin ever covered 

 once the three depressions of the Alatau, the Aral-Caspian, and 

 Siberian — the former was separated from the two latter at a 

 much earlier period than the time when, at least, a tluviatile 

 connection between the Aral-Caspian and the Siberian Ocean 

 had ceased to exist. The separation must have taken place 

 earlier than the separation of the two continents of Asia and 

 America. If a connection existed between the Balkhash and 

 the Irtish during the Post-Tertiary period, it could be only by 

 means of shallow streams where the Phoxini could live. On 

 the contrary, the Balkhash and the Lob-nor remained connected 

 after the above separation took place. The connection was 

 carried on through Kunges, the Yuldus, and Tarim. The limits 

 of this basin can be easily determined. 



Messrs. Swan Sonnenschein and Co. will publish in a few 

 days a "Tourist's Guide to the Flora of the Alps," translated 

 from the German of Prof Dalla-Torre, and issued under the 

 auspices of the German and Austrian Alpine Club of Vienna. 

 The volume will appear in the form of a handy pocket-book. 



The additions to the Zoological Society's Gardens during the 

 past week include a Chacma Baboon (Cyyiocephahis porcarius i ) 

 from South Africa, a Malbrouck Monkey (Cercopiihecus cyno- 

 suriis9 ) from West Africa, presented by Lieut. -Gen. G. W. -\. 

 Higginson, C.B. ; a Rhesus Monkey (Jilacocus r/usus'}) from 

 India, presented by Mrs. J. J. Buchanan ; a Macaque Monkey 

 {Macaais cynonwlgus 6 ) from India, presented by Mr. H. M. 

 Sharratt ; a Common Badger {MeUs taxus i ), British, presented 

 by the Hon. Walter de Rothschild ; four Moorhens {Gallhmhi 

 chloropus), British, presented by Mr. T. E. Gunn ; three Gold 

 Pheasants ( Thaumalea picta i i i) from China, presented by 

 Mr. A. Hey wood, F.Z. S. ; a Hygian Snake {Elaps hygiiv), a 

 Hoary Snake {Coronclla cana), a Crossed Snake [psamnup/iis 

 crucifer) from South Africa, presented by the Rev. G. H. K. 

 Fisk, C.M.Z.S. ; two Great Cyclodus {Cydodus gigas), two 

 Stump-tailed Lizards ( Trachydosaurus rugosus) a Diamond Snal;e 

 {Morelia spUotes) from Australia, received in exchange. 



OUR ASTRONOMICAL COLUMN 



Photographic Evidence as to the Constitution of 

 SUNSPOTS. — M. Janssen, remarking on some exquisite photo- 

 graphs of sunspots which he has obtained during the past year, 

 calls attention to the evidence they supply as to the continuation 

 of the granulation of the general solar surface into the spots. A 

 photograph of the great spot of 18S5, June 22, for example, to 

 which he particularly alludes, shows that the bright region 

 which surrounds the penumbras of large spots has not a different 

 constitution from that of the photosphere in general, since it is made 

 up in like manner of granular elements, usually of a spherical 

 form. The marked increase in brightness of such regions the pho- 

 tographs show to be due to the granulations being more thickly 

 clustered, brighter in themselves, and arranged on a brighter 

 baclcground. In the penumbra the granulations are still dis- 

 tinguishable, but they are less luminous and more scattered, 

 leaving dark gaps between the rows of grains, the familiar 

 striated appearance of the penumbra being due to the arrange- 

 ment of the granulations in ranks and lines, like beads on a 

 thread. The grains become in general smaller and duller near 

 the nucleus, where they seem to dissolve. The same spot pre- 

 sented two very remarkable bridges, and a very bright isolated 

 mass of luminous matter which united them. This luminous 

 matter and the bridges were also formed of granular elements 

 resembling the others. Many other photographs have revealed 

 a similar structure in penumbras and their surroundings, so that 

 it is highly probable that "the luminous matter which forms 

 the solar surface has everywhere the same constitution." 



The Strijctuke of the Solar Envelope. — A somewhat 

 lengthy paper by M. Trouvelot, on the above subject, originally 

 published in the Bulletin Astronomiqite for June, August, and 

 September last, has recently appeared. The first part of the paper 

 consists of a rvsunii of a number of striking and typical observa- 

 tions which are illustrated in the plate which accompanies it. 

 These observations principally relate to spots of irregular and 

 complicated form ; the most remarkable being those in which 

 M. Trouvelot describes the formation of numbers of bright 

 white points over sunspots, like "a fall of snow," sometimes 

 even obliterating them, the formation of purple vapours in 

 connection with both spots and prominences, and the ap- 

 parent changes and sometimes complete concealment of spots 

 occasionally produced by facula;. The essentially granular appear- 

 ance of the sun, so well brought out in M. Janssen's photographs, 

 has by no means escaped M. Trouvelot's notice, and he has even 

 seen the lines C Dj D2 b^ b-i b^ and F as themselves granulated, i.e. 

 not uniformly dark, but composed of a great number of whitish 

 points separated by dark intervals. The latter part of the paper 

 is occupied with inferences as to the constitution of the solar 

 envelope resulting from a consideration of these observations. 

 The theory formed resembles in its essential characteristics that 

 so admirably set forth by Prof Young in his book on the sun. 

 The sun is surrounded by a shell relatively very shallow, made 

 up of innumerable vertical filaments due to the condensation of 

 metallic vapours, and which M. Trouvelot proposes to call the 

 iieinalosphere, in distinction to the photosphere, the glowing 

 summits of these filaments. The behaviour of these filaments 

 under various circumstances is discussed, and the varying effects 

 upon them of hydrogen and metallic eruptions from the solar 

 nucleus below of different degrees of violence is made to ac- 

 count for the varied phenomena of spots, facula;, and promin- 

 ences. The brilliance of the photosphere is regarded as due 

 to the high radiating powers of these metallic vapours, when 

 on arriving at the surface of the sun they are condensed, partly 

 from the effect of exposure to the cold of space, and partly from 

 expansion, the granulations being glowing clouds composed of 

 these condensed metallic vapours, the summits of these filaments 

 or columns. 



M. Trouvelot expressly contradicts the frequently-made asser 

 tion that the bright D3 line of the chromosphere has no counter- 

 part amongst the dark lines of the spectrum of the disk ; the line 

 is indeed an exceedingly fine one, but it is unmistakably present. 



ASTRONOMICAL PHENOMENA FOR THE 

 WEEK 1886 FEBRUARY 7-13 



/"pOR the reckoning of time the civil d.ay, commencing at 

 ^ Greenwich mean midnight, counting the hours on to 24, 



is here employed.) 



At Greenwich on February 7 

 Sun rises, 7h. 30m. ; souths, I2h. 14m. 22'S3. ; sets, l6h. 58m. ; 



decl. on meridian, 15° 14' S. : Sidereal Time at Sunset, 



2h. 9m. 

 Moon (at First Quarter on Feb. 12) rises, 8h. 47m. ; souths, 



I4h. 39m. ; sets, 20h. 41m. ; decl. on meridian, 2° 12' S. 



Planet 



Ris 



Mercury ... 7 14 

 Venus ... 7 20 

 Mars ... 20 4* 

 Jupiter ... 21 14* 

 Saturn ... 12 46 



Souths 

 h. m. 

 II 26 

 13 " 



2 37 



3 14 

 20 57 



15 38 ... 20 30 S. 



19 2 ... 2 42 S. 



9 10 ... s 51 N. 



9 14 ... o 50 S. 



S 8* ... 22 41 N. 



The planet Venus is now very near to inferior conjunction. 



and the setting 



Occultations of Stars by the Moon 



Mag. 



Disap. 



Reap. 



Corresponding 

 nglesfrom ver- 

 2X to right for 

 nverted image 



B.A.C. 741 

 48 Tauri ... 

 7 Tauri ... 

 71 Tauri ... 



6| ... 18 6 ... 19 12 ... 157 286 



6' ... 20 40 ... 21 40 ... 93 347 



4 ... 22 45 ... 23 47 ... 128 323 



6 ... I 43 ... 2 25 ... 95 345 



