i84 



NATURE 



{Dec. 24, 1885 



The average heat-value of well-purified coal-gas at constant 

 volume has been recently determined by M. Witz {Ann. de 

 Chivi. et de Phys.) as about 5200 calories per cubic metre at 

 o" and 760 mm. when the water formed is fully condensed. This 

 value, got from a great variety of experiments with gas from 

 different works, appears to make the generally-accepted figure of 

 6000 calories about 15 per cent, too high, and the calculation 

 of gas motors is here concerned. The heat-value of the gas 

 from one and the same works varied in the course of a year 

 from 4719 to 5425 calories, which was more than the variation 

 between different works. The influence of temperature and 

 external pressure was not perceptible. The operations for puri- 

 fying gas diminish the heat-effect, sometimes as much as 5 per 

 cent. The gas of the last hour of distillation is (contrary to the 

 usual view) less rich than that of the first hour. Dilution with 

 oxygen lessens the heat-value ; but in dilution with air, 

 curiously, no such effect was observed ; the heat of combustion 

 was the same with six or with ten volumes of air. 



I.M his investigations of the changes of level of inland lakes 

 (known as seiches). Prof. Forel has arrived at the simple 

 formula t — I j \l gh for those movements, in which t expresses 

 the time, in seconds, of a half oscillati J 1 of a uninodal seiche, 

 I, the length, and h, the mean depth of the cross-section of the 

 lake in which the variation is observed. This formula holds 

 good for the lakes of Neuchatel, Brienz, Thun, Wallenstadt, 

 and Geneva. An interesting confirmation of it is found by 

 M. Forel in observations made by Mr. Russel with a limno- 

 graph ou Lake George in New .South Wales. This instru- 

 ment had recorded 33 very regular seiches on the lake this year, 

 and the duration of a whole oscillation proved to be 131 

 minutes. Now the length of the lake being 28,962 metres, the 

 above formula gives, for the mean depth, 5 '536 metres, or 

 18 •! feet. Mr. Russel states that the mean depth is between 

 15 and 20 feet. 



The prevailing direction of the winds on the shores of the 

 Black Sea and the Sea of Azov has been recently studied in 

 great detail, and in connection with the recent progress of 

 meteorology with regard to wind generally, by M. Spindler, 

 who has published his work, with maps, in the Russian Maritime 

 Revitw (Marskay Shornik). Four maps show the prevailing 

 direction of the wind at 7 a.m. and at i p.m. during the four 

 seasons of the year. During the winter a notable difference 

 between the prevailing direction at these two hours of the day 

 is seen only on the eastern shore ; while in the spring and 

 summer nearly everywhere on the Russian coa^t of the Black 

 Sea these two directions differ by 90", and at some places they 

 are quite opposite to one another, thus showing that the pre- 

 dominating influence of the currents of air depend upon the 

 different heating of land and sea. 



It is reported from Kara-hissar, in Asia Minor, that an earth- 

 quake shook that neighbourhood on Tuesday, December 2. 

 In the hamlet of Kemin the earth opened for a length of about 

 40 feet, and from 3 to 5 feet wide. 



The last earthquake shock in Algeria was felt at Blidah on 

 December 13, at 5 a.m. Subterranean noises were heard. The 

 first shock, in Hussein Dey, near Algiers, was felt on December 3, 

 at 8h. 23m. a.m. This has been proved by the stopping of a 

 clock in a distillery. 



How great are still the numbers of Carnivora in Finland may 

 be seen from the following figures, given in the last issue of the 

 " Statistical Yearbook " for Finland. In 1882 not less than 85 

 bears, 128 wolves, 407 lynxes, 4005 foxes, 76 gluttons, 240 river 

 otters, 148 martens, 15S3 ermines, and 3947 carnivorous birds 

 were killed, for which an aggregate of 1646/. was paid in 

 premiums by the Government. The ravages occasioned by Car- 



nivora the same year were immense : they are estimated at 274 

 horses, S46 horned cattle, 5246 sheep, 168 pigs, 119 goats, 1681 

 reindeer, and 2366 domestic fowls. The greatest number of 

 bears were killed in Viborg and Uleaborg (respectively l}, and 

 30), while most wolves were killed in the more densely-peopled 

 Government of Tavastehuus. 



At the meeting of the Royal Physical Society of Edinburgh, 

 held December 16, the following office-bearers were elected, 

 viz. — President: Prof. William Turner, F.R.SS.L. and E., 

 Edinburgh University ; Vice-Presidents : John A. Harvie- 

 Brown, F.R.S.E., Rev. John Duns, D.D., Prof. J. Cossar 

 Ewart, F.R.S.E. ; Secretary: Robert Gray, V.P.R.S.E. ; 

 Assistant- Secretary : John Gibson ; Treasurer : Charles Pren- 

 tice, F.R.S.E. ; Librarian : William Evans Hoyle, F.R.S.E. ; 

 Council : John Hunter, F.C.S., Robert Kidston, F.G.S., A. B. 

 Herbert, Prof. James Geikie, F.R.S., G. Sims Woodhead, 

 F.R.C.P.Ed., Hugh Miller, F.G.S., Arthur W. Hare, M.B., 

 R. Milne-Murray, M.R.C.P.E., H. Moubray Cadell, B.Sc, 

 R. H. Traquair, F.R.S., R. Sydney Marsden, D.Sc, F.R.S.E., 

 Benjamin N. Peach, F.G.S., F.R.S.E. 



The additions to the Zoological Society's Gardens during the 

 past week include a Macaque Monkey (Macacus cynomolgus) 

 from India, presented by the Rev. Spencer Fellows ; a Black- 

 backed Jackal {Caiiis mesomelas) from South Africa, presented 

 by Mr. J. Robson ; a Slender-billed Cockatoo {Licmetis tenui- 

 rostris) from .\ustralia, presented by Mrs. Sturt CaveU ; a 

 Kestrel {Tinnunculus alaudarius), British, presented by Mr. T. 

 E. Gunn ; three Wild Ducks {Anas boschas), British, presented 

 by Mr. C. T. McNiven ; a Lapwing {Vanellus vulgaris), British, 

 purchased. 



OUR ASTRONOMICAL COLUMN 

 Total Solar Eclipse, 18S6 August 28-29. — The eclipse 

 will be total throughout the Island of Grenada. The Greenwich 

 mean times of beginning and ending of totahty for any point in 

 the island may be found from the formulae : — 



Cos OT= -4-99=67 -[^^tSzs] sin /-I- [1-26284] cos ! co% (K + ^i' 13" S 

 <= ih. 12m. 41-75. =F [2-04698] sm w - [324330] sin / 



- [3-84970] cos / cos (\ + 82° S3'-o), 



where / is the geocentric latitude of the place, X its longitude 

 from Greenwich, taken negatively, and the quantities in square 

 brackets are logarithms ; upper sign for beginning, lower for 

 ending. 



For long. 4h. 6m. 20s. VV., lat. 11° S9''5 N. near l\ie southern 

 extremity of the island, totality begins at igh. Ilm. os. local 

 mean time, and continues 3m. 42s. g's altitude 20°. 



In long. 4h. 6m. 40s. W., lat. 12° I5''0 N. near the northern 

 extremity of the island, totality begins at I9h. 10m. 37s. local 

 mean time, and continues 3m. 37s. 

 At Carriacou I. (Grenadines) — 



Totality commences .at I9h. ilm. 45s. local M.T. 



Duration 3m. 21s. 



Sun's altitude 20° 



Fabry's Comet. — Dr. H. Oppenheim continues hisephemeris 

 of this comet in the Dun Echt Circular, No. 102, as follows : — 



JLphemeris for Berlin Midnight 



/3 Cygni or 6 Cygni ? — M. Flammarion in the December 

 number of V Astronomic falls into a curious confusion with regard 

 to these stars. Dr. Ball had found the parallax of B.A.C. 

 6579 (B) to be + o"-482 ± o"-o54, and following Bode's numbers 

 called the star 6(B) Cygni. Unfortunately, however, M. Flam- 

 marion supposed Dr. Ball referred to Flamsteed's 6 Cygni, which 

 is (8 Cygni, and based an article on the supposed determination 



