Proctor's Astronomical Lectures. 



3r 

 I 



tllllry Way and In It neighborhood, he concluded the 

 tarry system Is a great extension toward the zone of 

 the Milky Way, and because that zone is divided In one 

 part, he concluded the system Is cloven ID that direc- 

 tion, and he cauie to the conclusion that that system is 

 like a cloven disk. According to that theory, 

 the nebula? would appear to be a number of 

 galaxies of stars. 



WRIGHT'S THEORY OF THE UNIVERSE. 



But another astronomer noted that the Milky Way 

 was not of that uniform structure which the theory 

 of Wright seemed to require. It is like a cloud, and 

 there is sufficient to indicate that the Milky 

 Way consists of clouds of stars. The next picture will 

 bhow you a section of our starry svstein based oo that 

 view, and in (hat section there is supposed to be a mul- 

 titude of comparatively small spherical clusters of stars 

 According to Lambert, these spherical clusters form to- 

 gether a cluveu, flat disk. 



LAMBERT'S THEORY OF THE UNIVERSE. 

 Then came the work of Sir William Herscbel. And 

 here I point out that error in our books of astronomy, 

 repeated over and over again, of supposing Hprsehel's 

 theory to be that our starry system is like a flat disk. 

 It must be remembered that we cannot take the labors 

 of Herschel, extending as they do over half a century, 

 and treat all as if they all were part of one work. His 

 essays in the Philosophical Transactions cannot be 

 treated like a book written at once, and we must note 

 bow lie tells us that he hiuiself changed his mind 



But m the Milky Way he thousht tlio stnrs wor* Fp rp "fl 

 uniformly. "I am convinced." he- said, " by pro...,, ^ed 

 examination, that the stars in the Milky Way are differ- 

 ently spread from those which lie immediately around." 

 lie used the same telescope, and ho counted the stars 

 indifferent localities. That was the first part of lii.i 

 method. In other sets of observations he used different 

 telescopes; first a small one, and then a larger, and then 

 a still larger one, and he dealt with the difficult parts of 

 the heavens where the stars are clustered so 

 richly that the telescope refused to show them 

 separately; and then he used a more powerful telescope, 

 and considered that he was penetrating further and 

 further luto space. That was when he was nearly four- 

 score years of age, and there was a possibility that any 

 error In that method would not be detected by him, and 

 he failed to note that if he were looking at a small 

 cluster of stars, and looking at them first with a small 

 telescope and then with a more powerful and still 

 another more powerful one, if he were really passing 

 further and further on, that cluster, instead of beiug a 

 spherical group, would be spike-shaped, a projection of 

 stars extending out backward from our earth, which is 

 inconceivable, when we consider the immense number 

 of these clusters on our Milky Way. 



TViiat 1 wi>h anJ. iiopo to do, i.s to carry on that system 

 of star gau.ciug. combined with tlin system of Uarscnel ; 

 to take one telescope and survey tiie whole heavens, 

 counting the numbor of stars in dlffereut directions ; 

 not a fii-ld here aud a field there, as Hcrschei did, but field 

 after field, little square fluids, side by side, in the heavens, 

 counting the number and mapping the results ; and t'.iea 

 seeing where the stars shown by that telescope are 

 richly or poorly distributed. Then take a telescope o 

 higher, and afterward another of higher power; seeing, 

 after each set of observations, whether the rich regions 

 seen by one correspond wich the rich regions seen by 

 another telescope, and so knowing something of tho 

 heavens. Suppose you were looking at the sky and saw 

 large birds spread irregularly over it; if you noticed 

 that there were small birds also spread over it, th;it 

 where the large objects were the small ones were also 

 numerous, you would conclude that these large ar I 

 small objects formed a single cloud were intermixed ; J 

 it were and be certain that the large and the small 

 ones were intermixed in the same clouds. That conclu- 

 sion would be important in our star system. 



I pass to the results of the investigations of Sirur<5 

 of Germany, who numbered the stars and found that 

 large and small stars are rich in numbers in the Milky 

 Way, and inferred that there is an intermixture of them, 

 and that the star system has not the shape of a disk, but 

 that what was supposed a disk has no limits. I pass to 

 Bo;ne maps which I made as a beginning toward a sys 

 ten? of star gauging, and I have not been able to go fur; 

 but these few maps are an indication of the method. \ 



Here are all the stars on tho northern heavens, on a 

 scale absolutely necessary to this kind of work, of sur- 

 face projection, and you wi)l notice that here is the 

 Milky Way. and here are gatherings of stars. I invite 

 your attention to the dark region here. We shall now 

 the southern heavens brought on, and there la a 



