i;;2 



A'A TURE 



[December 6, 1894 



«n elementar)- atom compared with the atom of hydrogen. The 

 relative weight of this particularly heavy atom was determined 

 so long as forty-three years ago by Prof. Schneider, and the 

 value obtained was identical with that which is now afTorded. 

 Eight years after Prof. Schneider's first determination, Dumas 

 published the results of a number of atomic weight de- 

 terminations, among them being that of bismuth, to which he 

 assigned the value 210. From that time, 1859, until 1SS3, 

 Dumas' value came to be generally accepted, although no 

 doubt his method was by no means so little open to objection 

 as that employed by Prof. Schneider. However, in 1SS3 

 Marignac took up the subject, and as the result of determinations 

 carried out with the thoroughness for which he was remarkable, 

 the number 2o8'i6 was obtained, thus substantiating the work 

 of Prof. Schneider. More recently Classen has obtained a 

 higher result, 2oS'9, by an electrolytic method, and Prof. 

 Schneider has undertaken a further series of determinations with 

 the view of testing certain suggestions of Prof. Classen regard- 

 ing possibility of error in his former estimations. The method 

 is based upon a comparison of the equivalent relation of metallic 

 bismuih to bismuth trioxide. The final result obtained, if 

 O = 16, is 208 05, and the greatest divergence from this number 

 among the whole of the individual values is only o"2l. Prof. 

 Schneider's original work, and likewise that of Marignac, is thus 

 confirmed, and bismuth must now be added to the rapidly 

 growing list of elements whose atomic weights are represented 

 by whole numbers. 



The aiditions to the Zoological Society's Gardens during the 

 past week include a Sykes's Monkey (,Cercof>itheciis alhi- 

 gularis, i ) from West Africa, presented by Mr. J. II. Prestwich; 

 a Mozambique Monkey (Cercopithecus fygfryt/iriis, i) from 

 East .Africa, presented by Mr. C. O. Gridley ; a Leopard 

 (Felis pardus) from Southern India, presented by Mr. John 

 Christie ; two Spotted Eagle Owls (Bubo maculosa) from 

 South Africa, presented by Mr. R. A. Langford ; an Antipodes 

 Island Parrakeet (Cyanorhamphiis uiiicolor) from Antipodes 

 Island, seven South Island Thrushes ( Tiirnagra crassirostris) 

 from South Island, New Zealand, presented by Sir Walter L. 



Buller ; two Canary Finches {S,ri>iiis canariiis), (onr Frogs 



{Rana, sp. inc.) from Madeira, four Dwarf Chameleons, 

 (Chantuleon pnmilui) from South Africa, presented by Mr. H. 

 Bendelack ; a Rhomb-marked Snake (^Psammophylax rhom- 

 htalut) from South Africa, presented by Mr. J. E. Matcham ; 

 an .\rctic Fox (Canis lagopiis) from the Aictic Regions, 

 deposited ; four Nutcrackers {Ntici/raga earyocacles), European, 

 purchased ; sixteen Deadly Snakes ( Tiigonocephalm alro.x), born 

 in the Gardens. 



OUR ASTRONOMICAL COLUMN. 



The New Cumf.t. — The comet of which the discovery was 

 announced in the last number of Nature is likely to prove 

 a very interesting object. A communication from Prof. 

 Krueger informs us that Dr. Berberich, who is probably in pos- 

 session of ephemcrides of the lost comets depending on various 

 daleo of perihelion passage, has noticed the coincidence in the 

 positi'jn of this comet at the first observation with that which 

 De Vico's comet of 1844 can assume. It will be remembered 

 that it was thi< same aitrunomer who conjectured from some- 

 what similar grounds the identity of Holmes' comet with that 

 of Biela. But the conjecture in this case seems to be belter 

 founded, for elements computed by Dr. Leuschner show a 

 decided similarity with those of De Vico, as computed by the 

 late Dr. Ilrunnow from the 1844 observations. Seeing that the 

 comet has undergone some fifty years' perturbations since that 

 time, and that the present elements arc founded on the observa- 

 tions of but three consecutive days, and can only be considered 

 as roughly approximnte, we must be prepared for some con- 

 tiderable deviation. 



Leiischner's 



elements 



of Swift's 



comet. 



Brunnow*s 



elements 



of De Vico's 



comet. 



Long, of perihelion ... 291 48 ... 342 30 

 ,, nodes ... 43 4 ... dl 49 



Inclination 3 16 ... 2 55 



Minimum distance ... I '4703 ■■• l'lS64 



De Vico's comet has not been seen since 1844, though, with 

 a period of approximately five and a half years, nine returns 

 have occurred, and when the perihelia fall in the autumn, the 

 comet is fairly favourable for observation. There is extant, it 

 is true, an observation of a nebula by Goldschmidt in May 

 185s, which he thought might have reference to the comet, but 

 Brunnow could not reconcile it with the computed path, and it 

 is usually believed that the comet disappeared after observation 

 in 1844. But Le Verrier and Brunnow both thought that the 

 comet of 167S was identical with that of 1S44, and if this be the 

 case it would seem that the comet might be subject to fluctua- 

 tions of brilliancy, which would explain the fact of its passage 

 through perihelion without notice. 



Further, a similarity between the elements of Finlay (1886 

 VII.) and De Vico has been noticed, and the agreement be- 

 tween those of the present comet and FinKiy's is probably more 

 marked than with De Vico. Tisserand's well-known criterion 

 of identity does not favour the supposition that De Vico and 

 Finlay are one and the same comet, since a very considerable 

 perturbative effect would have to be attributed to the action of 

 Mars. It would seem, therefore, more probable that several 

 comets are moving in approximately the same orbits than that 

 we have to do with the actual return of a comet lost for so 

 long a period as De Vico's. But under any circumstances, seeing 

 that the comet is diminishing in brilliancy, it is of the utmost 

 importance to secure observations as early and as long as 

 possible, since upon the accurate determination of the orbit 

 several important questions may finally rest. The following 

 positions are given in the ephemeris received from Kiel : — 



R.A. Decl. 



lSc4. 1). m. S.1 , 



Dec. 6 23 2 52 ... -7 so'9 

 „ 7 23 s 40 ... -7 311 



The Si'ECTRU.M or Mars. — Prof. W. W. Campbell has 

 lately brought together all the observations of the spectrum of 

 Mars, and discussed them in connection with the telluric 

 spectrum and with his own observations made during the past 

 summer. {Ptil'Ikaliotis of iht Aflronomical Soticly oj tin Pcuific, 

 vol. vi. No. 37.) He concludes as follows : — 



(1) The spectra of Mars and the Moon, observed under 

 favourable and identical circumstances, seem to be identical in 

 every respect. The atmospheric and aqueous vapour bands 

 which were observed in both spectra appear to be produced 

 wholly by the elements of the Earth's atmosphere. The observa- 

 tions, therefore, furnish no evidence whatever of a Martian 

 atmosphere containing aqueous vapour. 



(2) The observations do not prove that Mars has no atmo- 

 sphere similar to our own ; but they set a superior limit to the 

 extent of such an atmosphere. Sunlight coming to the Earth 

 via Mars p.-isses twice either partially or completely through 

 his atmosphere. If an increase of 25 to 50 per cent, in the 

 thickness of our own atmosphere produces an appreciable effect, 

 a possible Martian atmosphere one fourth as extensive as our 

 own ought to be cielected by the method employed. 



(3) If Mars has an atmosphere of appreciable extent, its 

 absorptive effect should be noticeable especially at the limb of 

 the jilanet. Prof. Campbell's observations do not show an 

 increased absorption at the limb. This portion of the investiga- 

 tion greatly strengthens the view that Mars has not an extensive 

 atmosphere. 



VO. 13 10, VOL. 51] 



THE ANNIVERSARY MEETING OF THE 

 ROYAL SOCIETY. 



'T'lIE anniversary meeting of the Royal Society was held in 

 ■*• the aparlmcnts of the Society at Hurlinglon House on St. 

 Andrew's Day, November 30. The auditors of the Treasurer's 

 accounts having presented their report, the Secretary read the 

 lisls of Fellows elected and deceased since the last annivers.ary 

 meeting. The qualificaticn of the new Fellows on the home list 

 were given in Nati-RE of May l7(vol. I. p. 55). The new Fellows 



