485 



NATURE 



[September 17, 1908 



The .4/(1 delXa Fondazione Scientifica Cagnola (xxi.) 

 contains the reports of committees appointed to consider 

 tlie merits of various prize essays submitted. The re- 

 mainder (and greater part) of the volume contains an 

 elaborate essay, by Dr. Moschini, on the supra-renal 

 capsules, accompanied with a bibliography of fifty-five 

 pages, and illustrated with some excellent coloured plates 

 and tracings. 



OUR ASTRONOMICAL COLUMN. 



Comet igoSr. — .\ set of elements and an ephemeris for 

 comet iqoSc have been computed by Herr H. Kobold, from 

 observations made at Rome on September 3 and at Copen- 

 hagen on September 4 and j, and are published in a 

 supplement to No. 4272 of the Astronomische Nachrichten 

 (September 4). The following are taken therefrom : — 



Elements. 

 T = 1908 December 24-3175 M.T. Berlin. 

 00 =174° I3'i3i 

 a =105° 3'-3i > 19080 

 i =140° 36' 58 ) 

 log 57 = 9-96412 



Ephemeris 12/1. M.T. Berlin. 

 1908 a app. 6 .-ipp. log r log .i Brightness 



h. m. < 



Sept. 18 ... I 16-1 ... +75 399 ... 0-2651 ... 0-1325 ... 2-1 



,, 20 ... o 40-7 ... -H76 17-2 



,, 22... o 0-4 ... +76 31-9 ... 0-2530 ... 0-1039 ... 2 5 



,, 24 ... 23 17-2 ... 4-76 18-0 



„ 26 ... 22 34-6 ... +75 31-5 ... 0-2405 ... 00767 ... 3 c 



„ 28 ... 21 55-5 ... +74 I2-I 



,, 30 ... 21 21-8 ... -1-72 22-2 ... 0-2277 ■•■ 00520 ... 36 



The hazy, moonlit skies of the past week have mili- 

 tated against the observation of the comet in London, but, 

 as will be seen from the ephemeris, the comet is becoming 

 brighter, and will remain visible throughout the night 

 during the present month, so that observations of it are 

 very probable. The accompanying chart shows the 



URSA MINOR 



y -V 



DRACO 





1 + ^'* 



CEPHEUS 



Chart showing apparent path of Comet igoSc, September 12-30. 



apparent path of the comet, through the constellation 

 Cepheus, for the remainder of September. It may be 

 noted that at midnight on September 23 the comet will be 

 about 4m. E. and 36' S. of the 3-5 magnitude star 

 y Cephei. 



Observations made by M. Giacobini at Nice on Sep- 

 tember 3, 4, and 5, and published in No. 10 of the Comptes 

 reiuhis (September 7, p. 474), showed that the comet then 



NO. 2029, VOL. 78] 



appeared as a round nebulosity, of some 15" to 20' 

 diameter, having an ill-defined nucleus and a feeble con- 

 densation. .\ small tail, in position-angle 250°, was 

 suspected. When the field was illuminated gradually, the 

 comet disappeared with stars of the eleventh magnitude. 



Observations of Jupiter. — In No. 4272 of the .istrono 

 mische Nachrichten (p. 389, September 4) Prof. Barnard 

 briefly discusses some of his observations of the Great Red 

 Spot, and directs particular attention to the peculiar re- 

 pellent action of this spot, acting on tlie material of the 

 south equatorial belt to form the Red Spot Bay. In the 

 earlier observations of 1879, and again in 1885 and i8Sb, 

 the bay was strongly marked, the material north and 

 following the spot on the southern edge of the equatorial 

 belt being apparently repelled, and leaving a clear, 

 symmetrical interval between the main body of the belt 

 and the spot itself. Since then the spot has, to a great 

 extent, lost its red colour, and has, apparently, become 

 greatly enfeebled, yet this repellent action has apparently 

 persisted as strongly as ever ; at the present time the matter 

 of the equatorial belt has advanced so far southwards as 

 to enclose completely the spot, yet a clear, narrow space, 

 symmetrical in figure with the spot, isolates the latter 

 object entirely from the surrounding material of the belt. 



In the same journal Father Chevalier, of the Z6-s4 

 Observatory, places on record the results of his observa- 

 tions of an occullation by Jupiter of the star BD-l- 19^.2095 

 on May 21. 



The Franklin-.\dams Photographic Chart. — In a letter 

 to the Observatory (p. 354, No. 400, September) Mr. 

 Franklin-.\dams states that, with propitious weather con- 

 ditions, he hopes to finish his chart photographs of the 

 northern hemisphere early in October. Those already com- 

 pleted have proved so successful that he fears that some 

 of the plates for the southern hemisphere will have to be 

 repeated in order to compare favourably with the northern 

 plates. The counting and classification of the star images 

 is to commence at once, experimentally and tentatively, 

 and Mr. Franklin-Adams intends to lay his proposed 

 method before an early meeting of the Royal Astronomical 

 Society in order that he may receive the general advice 

 of those experienced in such work. 



.'\no.malous Forms of the Calcium Line, K, in Promin- 

 ences. — In No. 24, vol. ii., of the Mitteilungen der 

 Nikolai-Hauptslentwarte zii Pulkowo^ Prof. Belopolsky 

 discusses the results obtained during 1906-7 in a photo- 

 graphic research on the anomalous forms of the " K " 

 line of calcium in prominences photographed at the sun's 

 limb. 



7'he object of the observations was to study the motions 

 of material at the sun's surface, and to provide data for 

 the discussion of the question of anomalous dispersion. 

 Prof. Belopolsky gives three plates of reproductions of 

 some of the forms recorded, together with full details of 

 the measurements and a brief discussion of the results. 



The Hypothetical Parallaxes of Double Stars. — 

 From a study of fifty-four binary stars of which the proper 

 motions are generally known, and for which he has calcu- 

 lated the hypothetical parallaxes, Dr. Doberck has obtained 

 some interesting results, which he slates briefly in No. 

 4271 of the Astronomische Nachrichten. 



On the assumption that the annual parallax is, on the 

 average, one-fifteenth of the proper motion, the masses of 

 the two components should average thirty-six times that 

 of the sun, but in the few cases where the paralla.x has 

 been determined it is indicated that each single star is, 

 on the average, only some 1-3 times the mass of the sun. 

 It is also shown, in these results, that the hypothetical 

 parallax amounts to about one-seventh of the proper motion 

 where the latter is large, is equal where it is small, and 

 is about o"-03 where the proper motion is too small to be 

 determined. 



From the figures given it appears that the hypothetical 

 parallax is not a function of the magnitude ; even in the 

 case of stars of the sixth magnitude, at which rapidly 

 revolving double stars are most common, the individual 

 results differ greatly inter se, whereas hypothetical parallax 

 and proper motion are very closely related. 



