July 14, 1887] 



NATURE 



257 



vertical diameter, 1851-83, and from the Neuchatel 

 servations, of horizontal diameter only, for 1862-83. The fol- 

 ding table shows the discordances from the mean for each 

 )nth of the year for the two series : — 



ASTRONOMICAL PHENOMENA FOR THE 



WEEK 1887 JULY 17-23. 



/ p*OR the reckoning of time the civil day, commencing at 



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



' here employed. ) 



At Greenwich on July 17 

 ^un rises, 4h. 4m. ; souths, I2h. 5m. SO'Ss. ; sets, 2oh. 7m. ; 

 decl. on meridian, 21" 13' N. : Sidereal Time at Sunset, 

 I5h. 48ro. 

 Moon (New on July 20) rises, ih. 19m,; souths, 9h. om. ; 

 sets, i6h. 50m. ; decl. on meridian, 17° 15' N. 

 Planet. 



Mercury 

 Venus ... 

 Mars , . . 

 Jupiter... 

 Saturn... 



Rises. 



h. m. 



1 59 

 8 23 



2 14 

 12 43 



4 u 



Souths, 

 h. m. 



13 14 



IS 6 

 10 35 

 18 o 

 12 12 



Sets, 

 h. m. 



20 29 



21 49 

 18 S6 



23 17 

 20 13 



Decl. on meridian. 



13 45 N. 



7 S3N. 

 24 I N. 



9 15 S. 

 21 6N. 



July. 



17 .. 

 17 .. 



i8 .. 



July. 

 19 

 21 



Occultations of Stars by the Moon (visible at Greenwich). 



Corresponding 

 Disap 



Star. 



85 Tauri .. 

 Aldebaran 

 115 Tauri.. 



h. 

 ,.. 4 ... 

 .. 17 ... 



Mag. 



.. 6 

 .. I 

 .. 6 



Reap, 

 h. m. 



1 45 

 3 33 



2 40 



angles from ver- 

 tex to right for 

 inverted image. 



30 286 

 139 172 



73 237 



Saturn in conjunction with the Sun. 

 Mercury in conjunction with and 3° 40' south 

 of the Moon. 



Star. 

 U Cephei ... 



R Corvi 

 5 Librae 

 U Coronse ... 

 U Ophiuchi ... 



W Sagittarii 



U Sagittarii... 



R Scuti 



S Sagittse ... 



S Aquarii ... 

 S Pegasi 



Variable Stars. 

 R.A. 



h. m. 



o 52-3 



... 81 



Decl. 

 i6N. 



July 



12 I3-S 



14 54-9 



15 13-6 ... 32 

 17 IO-8 ... I 



17 57-8 



18 38 S. 



8 4S. 



4N. 



20 N. 



18 252 



18 41-5 



19 509 



29 35 S. ... 



19 12 S. ... 

 5 50 S. ... 

 16 20 N. ... 



17, 22 32 m 

 22, 22 II m 



20, M 

 22, 23 id m 

 22, 20 54 m 



21, 2 31 m 

 22 38 m 



17, 21 o m 



... 22 si'i ... 20 57 S. . ,, 

 ... 23 14-8 ... 8 18 N. ... ,, 



M signifies maximum ; m minimum. 

 Meteor- Sho-wers. 

 R.A. Decl. 



21, 



22, 



23. 

 20, 



23, 

 18, 



18, 



o M 



o m 



M 



O 711 



oM 



M 

 M 



Near o Cassiopeiae 



.. 63Cygni... 

 From Cassiopeia 



II 

 315 



350 



+ 48 

 47 

 52 



Very swift. Streaks. 

 Swift. Short. 

 Very swift. 



GEOGRAPHICAL NOTES. 



The July number of the Proceedings of the Royal Geo- 

 graphical Society contains a detailed report of the paper read 

 by Dr. Junker on his explorations in Central Africa. Mr. 

 Delmar Morgan contributes, from Russian sources, a long 

 account of Russian geographical work in 1886, which contains 

 much that is interesting. One of the most important Expedi- 

 tions was that under J. V. IgnatieflF, to explore the magnificent 

 Khan Tengri group of mountains in the Thian Shan, whose 

 summits soar to a height of 22,000 to 24,000 feet. The botanist 

 of the Expedition, A. N. Krasnof, made some extremely im- 

 portant investigations, with especial reference to the flora of the 

 high snow and ice regions of the Thian Shan, as compared with 

 that of the Polar regions recently worked up by Wittrock. M. 

 Krasnof is of opinion that the valley of the Hi once 

 had an entirely different vegetation to that possessed by 

 it now, and that this early plant-life has completely 

 perished owing to the desiccation of Central Asia and the 

 consequent change in its climate. Formerly, M. Krasnof says, 

 the whole flora of the Hi valley was similar to that still pre- 

 served at the foot of the snowy mountains, resembling that of 

 Central Russia. At present all the lower chains are deprived of 

 the moisture they derived from melting ice-fields, and have 

 changed their flora in the most radical way, having now only 

 Central Asian forms. M. Krasnof s general conclusions are that 

 formerly the Thian Shan flora was intermediate between the 

 Altai and the Alpine, and resembled more closely that of the 

 Central and Northern Caucasus. The process of desiccation began 

 in the south, and showed itself by the formation of detritus, retreat 

 of the glaciers, and disappearance of lakes. It caused the forma- 

 tion of loess deposits, sand, and pebble-strewn plains, while it 

 diminished the areas of marshes and black-earth deposits. All 

 plants common to Polar and Alpine regions disappeared from the 

 southern slopes and syrts, while coniferous and deciduous arbor- 

 escent vegetation also vanished from all waterless slopes. 

 Wherever the snow has ceased to lie, the ancient flora has also 

 perished, only a few species having adapted themselves to a 

 continental climate and assumed an Asiatic character. 



The current number of Petermann's Mitteilungen contains 

 several papers of special scientific interest. M. Yokoyama con- 

 tributes an account of a paper by J. Tanaka, on the vegetation 

 zones of Japan, while Herr Ernst Hartert describes the botani- 

 cal results of his journey along with Herr Standinger in the 

 Western Soudan. Dr. Supan's paper on the climate of Europe, as 

 regards the duration of a certain mean temperature in different 

 areas, will be found of great value in working out the physical 

 geography of Europe. Dr. Supan's object is to show the 

 length of time (the number of months) a mean temperature — low, 

 temperate, or high — prevails in a European area, and to mark 

 off on maps the areas in which the temperature endures, the 

 number of months being expressed by colours. Many geographi- 

 cal and biological considerations depend on such general facts 

 of climate as Dr. Supan is endeavouring to work out. He 

 divides temperature into three classes : (1)0° Cent, and under, 

 which he calls the " Frost Period " ; (2) io° to 20° C, the 

 " Warm Period" ; (3) 20° C. and over, or the "Hot Period." 

 The duration of these temperatures he has noted at 471 different 

 stations in Europe and the countries round the Mediterranean. 

 The results, which he has represented cartographical ly by 

 areas of colour, may be briefly summarized thus : — The lines 

 of equal duration of the "Frost Period" run similarly to the 

 winter isothermal lines, changing from a southerly direction 

 in the West of Europe to a south-easterly and then east- 

 south-easterly in the East of Europe. As regards the " Warm 

 Period," it is only on the Atlantic side of Europe that the lines 

 of equal duration run distinctly south-east, elsewhere on the 

 Continent they approximate very nearly to the parallels of lati- 

 tude ; while for the "Hot Period" they show a north-easterly 

 direction. Thus in all three maps the contrast between the 

 oceanic west and the continental east comes out very sharply. 

 A glance at Maps i and 2 explains why the Norwegian highland 

 was in the Glacial epoch the birth-place of North European 

 land-ice ; the reason is not to be found in the extraordinarily 

 low temperatures, but in the duration of the cold and warm 

 periods. In all districts where a coast range of mountains inter- 

 poses between the interior and the sea, or where the hills rise 

 abruptly from the sea, the lines of equal duration press closely 

 together, notably in Norway and the Alps. Dr. Supan em- 

 phasizes the importance, in considering th^ climate of Eurooe 



