151 



KNOWLEDGE 



[July. 1902. 



photograplis, nltlimigh it is ccrtiiiiily Btrango that nil those yum 

 ^ll<>ul(l liiive niipciired in the southcTii hi'iiiis|ihoro. 1 therefore 

 ropuh'cil to coDiiiienec ii soiirch for new stnra." 



Dr. Anderson's purpose was not coiifiiioil to stars visible 

 to the niiktd pye, but exti-uded to all stars included in 

 the great work of Ari,'elaiider and Silujnfeld. This 

 necessitated his n\akiii^' eliarls for himself for the re^c'ions 

 south of + 40", a work which uioant the plottin;,' down 

 from their catalojj;ue places of more than 70,000 stars. 

 The instruments with which he worked were a large 

 binocular and two refractors, one of 2^ inches, the other 

 of 8 inches aperture, and which respectively enabled 

 him to see stars of the 10th and 11th magnitude. To 

 continue his own account : — 



"Thus armed I began to luint for 'new stars.' I worked with 

 might and main, never going to rest as long as the sky remained 

 clear, and often rising in the night to see if the clouds had passed 

 nwav, and if they had, hurrying downstairs to begin work either 

 uith the binocular oi' with the telescope. The chief obstacle that I 

 have to contend with in such work is that the only windows in this 

 house from which I can thoroughly examine the heavens, face the 

 north-west. Not only is my field of labour thereby very greatly 

 circumscribed, my telescope being only able to command that part 

 of tlie heavens which extends from the Equator to +70°, but the 

 discomfort is frequently not inconsiderable, as the northerly and 

 north-westerly winds, which so often bring with them transparent 

 and unclouded skies, are in winter and early spring far from being 

 balmy, and can make themselTes felt even when the window 

 shutters are partially closed. 



" At first my search was mainly for Novce, and was prosecuted 

 by means of my binocidar. . . AVhen I came to see that 

 hunting for Novce was not attended by the success whicli I had 

 anticipated, I began, without entirely abandoning such work, to 

 make a systematic search for variable stars. For this I used my 

 2i-inch telescope, comjiaring what it showed me with the repre- 

 sentation of the heavens contained in the B.D. charts 



I was always glad if after three or four months of searching, during 

 which I might have examined perhaps 20,000 stars and suspected 

 fifty or sixty of variability, I was able at last to come across one 

 whose brightness changed. 



" I found Nova Pcrsei, I need hardly say, without either 

 binocular or telescope when I was casting a casual glance roimd the 

 heavens." 



It was then no mere happy chance that the Council of 

 the Royal Astronomical Society were honouring, but the 

 most persistent and strenuous work, when at the annual 

 meeting of February, 1902, they conferred upon Dr. 

 Anderson the Jackson-Gwilt Medal. The words of the 

 President to him, when presenting the medal, put the case 

 briefly and clearly. 



'■Nova Auriga; was discovered by you on February 1st, 1892, 

 when of the 4th magnitude, and but for your discovery it might 

 liavc escaped observation. Nova Persci was discovered on February 

 22nd of last year at 2.40 a.m., when of 27 magnitude and low 

 down in the sky. This early discovery of yours made it possible for 

 Pickering to obtain its spectrum before its maximum was reached. 

 It is no small matter to have discovered one of these Norte, but it is 

 a veritable ioiir <ie force, such as i? priori would have seemed im- 

 possible to have discovered both, and I am delighted that we have 

 the opportunity to congratulate you on your success and to do honour 

 to your astronomical zeal and intimate knowledge of the sky." 



One point with regard to the discovery of Nova Persei 

 deserves further mention, namely that Dr. Anderson's 

 discovery was made almost simultaneously with the out- 

 burst, for {)hotographic records show that so late as 

 February 19th the star must have been fainter than the 

 nth magnitude. It had probably only entered the ranks 

 of stars visible to the naked eye a very few hours when 

 Dr. Anderson remarked it. But it is gratifying to remark 

 that whilst, but for Dr. Anderson, Nova Aurigte would 

 have passed entirely without detection, the closer watch 

 whi(h is now kept upon the sky resulted in several 

 entirely in lepandent discoveries of Nova Persei. Herr F. 

 Grimmler discovered it the same morning at Erlangen ; 

 Captain P. B. Molesworth at Trincomali was not quite 



twelve hours aff<>r Dr. Anderson, and four liours later 

 still Mr. Ivo Carr Gregg, at St. Leonards, had also 

 detected it, and communicating his observation to Col. 

 K. E. Markwick, the Director of the Variable Star Section 

 of the British Astronomical Association, the other 

 members of that Section were made aware of the event 

 before the news of Dr. Anderson's discovery had reached 

 them through the ordinary channels of information. 



DISTANT WORLDS. 



I.— A REVIEW OF SOME RECENT STUDIES 

 IN STELLAR DISTRIBUTION. 



By C. Easton. 



Everything is relative. This maxim applies to things 

 celestial as well as to things terrestrial. The planet Mars 

 is a distant world, but the distance which separates us 

 from it is insignificant when compared with the abyss 

 which yawns between the sun and the nearest stars: Alpha 

 Centauri, Sirius, Arcturus, which are distant 3, 9, 20 ligkt- 

 1/ears. Yet these worlds touch upon us, so to speak, for 

 the confines of our stellar system, of the Galactic system 

 (and perhaps there exist other galaxies in the depths of 

 space), are situated, according to Seeliger, at a distance a 

 thousand-fold greater, at a distance so stupendous that I 

 cannot resist the temptation to express it in kilometres ; — 



100,000,000,000,000,000. 

 There is no need for me to insist on the point that this 

 value is not a precise one. Nevertheless, it is based on 

 serious calculations and deductions, and it can at least 

 give some idea of the order of distances with which we 

 have to deal when we undertake the study of the Milky 

 Way. As for the number of stars contained in the 

 system, it is probably not less than GO millions, and is 

 perhaps still greater ; so that the total number of stars 

 visible by the naked eye — about 6000 — forms only a 

 negligeable quantity of this prodigious sum, and even the 

 900,000 stars above the 9th or 10th magnitude, enrolled 

 in the "Durchmusterungs" of Argelander and Schoenfeld, 

 of Gill and Kaptejn, constitute but an insignificant 

 fraction. 



I have referred to distances and numbers as prodigious 

 as these at the beginning of the article, since they may 

 serve as an excuse for not being yet able to present 

 striking and definite results, when I pass in review what 

 astronomers have found out about the structure of the 

 visible universe in the last four or five years, and both life 

 and progress are rapid in these days. Astronomy, as an 

 exact science, is still young ; it cannot venture far from 

 its homestead, the earth, without tottering steps, and the 

 objects which we study here are all near our horizon. 

 How comparatively easy would these researches become if 

 we could transjjort ourselves for a moment outside the 

 Milky Way, near one of the poles of our stellar system. 

 But the Milky Way surrounds us on all sides, and we are 

 somewhat in the position of a stranger who finds himself 

 suddenly planted on London Bridge, and who tries to 

 study the configuration of the metropolis without being 

 able to climb a tower. He would find some indications to 

 guide him in the trend of the river, the directions of some 

 principal streets, and in the crowd which surrotmds him, 

 but for the rest he must trust to the guidance of indirect 

 reasonings. The mind of man is in much the same case 

 when it tries to ]irobe " C'es fouriuilih-cs th rahiiiw," as 

 Victor Hugo calls the Milky Way. 



Nevertheless, from what follows, I hope we shall see that 

 our knowledge of the structure of the universe has made 

 reiil and substantial progress since the epoch — 1898 — when 



