202 



KNOWLEDGE 



[September 1, 1900. 



bined and discussed according to approved methods 

 The greater the number of observations the nearer the 

 approach will be to accuracy. So many observers now 

 occupy themselves with these observations that in- 

 dividual deductions, as regards rotation periods, had 

 better be discontinued in favour of a collective effort 

 to ensure safe and certain results. The plan of reduction 

 initiated by Mr. Marth, and followed by Mr. A. S. 

 Williams, Kev. T. E. K. Phillips, and others, is to be 

 greatly commended, and there seems little doubt that 

 in future years it will be generally adopted, and be the 

 means of vastly increasing our knowledge of the surface 

 vagaries of this wonderful planet. 



In the drawings of Jupiter accompanying this paper 

 no attempt has been made to show the slight curvature 

 of the belts due to the inclination of the planet in 

 1898 and 1899. 



[It should be lioted that this iia.per was wiitteu in Aiiril, 

 1900.— Eds.] 



THE HUNDRED BRIGHTEST STARS. 



By J. E. Gore, f.r.a.s. 



We sometimes hear of " the Hundred Best Books,'' and 

 there is much difference of opinion as to what thesj 

 books are. But there caai be little or no doubt as to th? 

 hundred brightest stars in the heavens, although the 

 exact order of their arrangement — or sequence, as it is 

 termed — may be somewhat uncertain. In the following 

 table I have arranged the hundred brightest stars in 

 the sky in the order of magnitude as measured with 

 the meridian photometer at Harvard College Observa- 



tory (U.S.A.), and at Arequipa, Peru. For the stars 

 visible in the Northern hemisphere the results are given 

 in the " Harvard Photometry " (HP.), and in the 

 Revision of the same recently published, and for the 

 Southern stars in the " Southern Meridian Photo- 

 metry " (S.M.P.). When a southern star occurs in all 

 three catalogues I have taken the magnitude given in 

 the S.M.P., as the observations were evidently mad3 

 under more favourable conditions. I have also given 

 the magnitude of each star as measured with the wedge 

 photometer at Oxford, and also in the Potsdam photo- 

 metric catalogues (recently published) whenever the star 

 is found in these catalogues. To make these catalogues 

 strictly comparable it should be noted that the standai'd 

 star Polaris is 2.15 magnitude in the H.P. and S.M.P. 

 catalogues, 2.05 in the Oxford, and 2.34 in the Potsdam 

 catalogue. The spectrum of the stain's light is given 

 from the " Draper Catalogue of Stellar Spectra," when 

 the star is found in that catalogue, I. denoting the 

 Sirian type, II. the solar type, and III. the third type 

 Some are given from the Harvard Annals, Vol. 

 XXVIIT., Part I., and a few from other sources. I 

 have also added the star's parallax and proper motioa 

 where these have been determined. I have placed the 

 stars in order of brightness according to the H.P., as ia 

 that catalogue the comparison star was Polaris, a com- 

 paratively bright star, while in the Revision of the H.P. 

 the comparison was X Ursaj Miuoris, a faint star 

 (G.57). 



The position of the stai-s are given for 1900.0, and 

 the list may be useful to variable star observers as afford- 

 ing comparison stars for naked eye stars suspected of 

 variation in light. 



