2S2 



NA TURE 



[January 17, 1S95 



chlorides, another series of experimenls hive been carried out 

 by a method which Prof. Winkler states is in his opinion 

 (and there can be none higher as regards work with the 

 two metals in question) quite unimpeachable. The older 

 methods based upon the electrolytic determination of 

 the metals were found to lead to an error in the 

 case of cobalt, owin» to the fact that a smill quantity of the 

 hydrated oxide Co.03-2H .0 is contained in the deposit upon 

 the platinum electrode, while in the case of nickel no oxidation 

 whatever occurs. This discovery was consequent upon another, 

 na-nely, that a solution of iidine in potassium iodide of deci- 

 normal strength is capable of instantly dissolving the deposited 

 metal from the platinum terminal without in the slightest 

 attac'<ing the latter, producing a solution of the iodide of the 

 metal. In the case of nickel the platinum is left perfectly 

 clean, while deposited cobalt invariably leaves a stain due to 

 about half per cent, of oxide. The electrolyticilly-deposited 

 cobal; employed by Prof. Winkler was therefore all reduced in 

 pure hydrogen before use ; when subs:queatly dissolved in the 

 iodine solution, no trace of oxide was ever left. The method 

 of analysis consisted in determining, by titration with pure 

 sodium thiosulphaie, the excess of iodine left after solution of 

 the pure metals to form the iodides. Two complete series of 

 analyses, each consisting of a considerable number of indi- 

 vidual determination-, were carried out with an interval of some 

 months, in order to employ metals from totally independent 

 mineral deposits. The results are most concordant, and lead 

 to the final numbers, Xi = 58-2 and Co = 5937, when H = i 

 and I = 1 26 53. The atomic weight of cobalt must therefore 

 be accepted as at least half a unit higher than that of nickel, a 

 result likewise in accordance with the work of Prof. Winkler 

 published a short time ago. 



OUR ASTRONOMICAL COLUMN. 



5 CeI'HEI. — Further particulars of Dr. Belopolsky's spectro- 

 scopic study of this variable s'ar (N.^TtKE, November I, 1894, 

 p. 21) are given in the BulUlin of the Si. Petersburg .V.-ademy 

 of Sciences, November, 1S94, and some of his numerical results 

 are slightly changed. He has shown for the first time that 

 orbital movement is as closely associated with this class of 

 short-period variable stars as with those of the Algol class, in 

 which the minima are produced by eclipses. Alihough the 

 spectrum of 8 Cephci is described as of Vogel's Class 11. (j, it is 

 pointed out that it differs fr.im that of the sun in many respects, 

 some of the lines which are narrow and feeble in the sun being 

 strong in the slar, and vi<e versa. There does not appear to be 

 any change in the character of the spectrum, other than a varia- 

 tion of intensity, as the light of the slar changes. 



The displacements of the lines with respect to the comparison 

 spectra of iron and hydrogen indicate that the slar has an 

 '.r'ji'.il movement in a period corresponding to that of the 

 li.;h- changes '5. 1, oh.), and that th-; eccentricity of the orbit is 

 o 514. The form ol the curve of velocities which is given, indi- 

 cates that the major axis of the orbit must be very nearly 

 directed towards the earth, and the system is approaching the 

 ca'th with a velocity of about 12 linglish miles per second. 

 With reference \n the centre of movement, Ihe maximum 

 \ and recession are about 13 English miles 



\ receding for about a day after minimum, 



3 day.s more, and receding until mini- 

 ron is the point of the orbit farthest 

 I IS passed about a day after minimum. 



I ne apparent .semi axis major is about 8l8,8co English 

 mile<, so that the whole oibil is less than twice the sun's dia- 

 meter. We are not aware that any attempt has been made to 

 determine Ihe parallax of the star, but unless it has a very high 

 emissive power, its small size would indicate that it must be 

 relatively near to us. 



.Notwithstanding thot Ihe lime of a possible eclipse is a day 

 after Ihe minimum of the light curve, iJr. HclopoUky scemsto be 

 of opinion thai the variation may he due to eclipsing, lie 

 app<ar« to believe that further work may show that there is 

 some systematic error, and that peiiastron may really coincide 



NO. 1316, VOL. S'] 



wilh the minimum. As the light changes appear to be going 

 on continuously throughout the period, it is clear that the 

 eclipsmg cannot be of the simple kind wilh which we are 

 familiar in the case of Algol. 



The V.\tic.^n Observatory. — K day after the death of 

 Father Denza, we received the fourth volume of the " Pubbli- 

 cazioni della Specola Vaticana." Every annual report of the 

 work done at the Vatican Observatory is more voluminous than 

 the one preceding it. The volume which came to us last month, 

 and to which Father Denza's death gives a melancholy interest, 

 runs into more than six hundred pages, and is illustrated by 

 forty-two plates. .-Vmong these are illustrations of Ihe Dumb- 

 bell nebula in Vulpecula, the Pleiades nebula, the Orion nebula 

 after exposures of thirty minutes and of nine hours, two photo- 

 graphs of the eclipse of .April 1S93, a photograph of the sun 

 with the big spot of August 1S93, together with two enlarged 

 pictures of the spot, and a map showing the direction of motion 

 of the meteors observed on August lo-li of the same year. 

 Papers on the subjects of the illustrations make up the greater 

 part of the astronomical section of the report. Altogether, ten 

 photographs were taken at Rome during the eclipse of April 

 1S93, and contact observations were also made. The numerous 

 meteorobservations made under Father Uenza'sdirection in Italy, 

 in August and November 1 89;, are catalogued and commented 

 upon. It is to be hoped that the system of meteor-observation 

 which the late Director instituted will not be allowed to lapse. 

 In celestial photography we note that in addition to the work 

 for the photographic chart and catalogue, 248 photographs were 

 taken of various cele-tial objects, 150 being photographs ol the 

 sun. Hut the astronomical results by no means represent the 

 total work carried out at Ihe observatory. .Meteorology and 

 terrestrial phisics come in for a large share of attention. To 

 us it seems that the only thing wanting to make the Vatican 

 Observatory a true astro-physical observatory is a section for 

 spectroscopic investigations. 



Many astronomers will be interested to know that a full and 

 appreciative notice if Father Denza's life and work has been 

 written by P. Armani, of the Collegio dei S.S. Biagio e Carlo. 

 Another full notice appeared in Comios of December 22. 



An iNmsPENSAiiLE .Annl'aire. — This year is the centenary 

 of the creation of the Bureau des Longitudes, the invaluable 

 Aii'iuairc of which has been received for 1S95. It is quite un- 

 necessary to remind astronomers of the merits of this veritable 

 : ade III c<:ii III , for they know its usefulness better perhaps than 

 workers in the other branches of physical science to which it 

 appeals. .-V few changes have been made since the previous 

 issue. M. Berthelot has completely revised and corrected the 

 tables relating to thermo-chemislry. M. Moureaux has in- 

 serted in the tables of the magnetic elements in France, the 

 values determined directly by him in 1894, at nearly six 

 hundred places. Prof. (ILasenapp has added five new stars to 

 his table of the elements of the orbits of double stars. The list 

 of comets has been brought up to Ihe end of 1893, and that of 

 minor planets up to November 1894. There are live articles in 

 the volume, the subjects and authors being : Lunar atmospheric 

 waves, by M. Bouquet de la Grye ; the Geodetic Congress at 

 Innsbruck, by M. Tisserand ; the Observatory on Mont Blanc, 

 by M. janssen ; photographic photometry, by the same author; 

 and a report on the proposition to unify the .astronomical and 

 civil days, by M. Poincarc (see the next note). 



TllK U.S'II-ICATION 01-- Civil, ANII ASTRO.VOMICAI. DAYS.— 

 It will be remembered that in 1893, the Astronomical and 

 Physical Society of Toronto invited replies from astronomers to 

 the question : " Is it desirable, all interests considered, that 

 on and after the first day of January 1901, the Astronomical 

 Hay should everywhere begin at moan midnight ?" Theresull 

 of the voting was noted in Nature, April 5, 1894, p. 542; 

 and to this may now be added the following resolution adopted 

 by the IJureau des Longitudes upon the <|ucstion (Aniiiiaire (or 

 1895): — "The Bureau des Longitudes is lavourable, in prin- 

 ciple, to the reform proposed by the Canadian Institute to 

 change the time from which to reckon the astronomical day. 

 The Bureau thinks that this reform, as has been observed by 

 the Lords of the .\dmiraliy, will be of little avail unless an 

 undcistanding is come to between tlic Governments publishing 

 the principal ephcmerides. Finally, considering that the 

 unification will not really be complete until the civil hour is 

 reckoned from o to 24 hours, as is Ihe case in Italy, the Bureau 

 is of the opinion that this reform ought to be realised as soon as 

 possible." 



