554 SCIENTIFIC RECREATIONS. 



continuous zone. Let the naked eye rest thoughtfully on any part of it, 

 and if circumstances are favourable, it will stand out rather as an accumu- 

 lation of patches and streams of light in every conceivable variety of form 

 and brightness ; now side by side, now heaped on each other, again spanning 

 across dark spaces . . . and at other times darting off into the neighbour- 

 ing skies in branches of capricious length and shape, which gradually thin 

 away and disappear." 



The Milky Way has its greatest breadth in the " Swan," and in the 

 "Eagle" constellation it divides itself. In the "Southern Triangle" the 

 zone is brightest, and in the " Southern Cross" the hole or space, termed by 

 sailors the " Coal Sack," is very distinct. It then contracts and expands, 

 and there is in Argo another gap. Then it is lost for a space, then it 

 branches out, and soon crosses the Equator, dilates, contracts, opens out 

 again, and so returns to the " Swan" again. 



Philosophers have frequently discoursed upon this phenomenon, but all 

 statements must remain more or less speculative. From Kepler's to the 

 present time astronomers have been considering the Milky Way, and when 

 the Nebular theory was given up, when the Galaxy was found to be com- 

 posed of stars, there was, as we have noticed, the idea of the ring and 

 the cloven disc. Mr. R. Proctor has likened the Galaxy to a coiled serpent, 

 and considers the openings in the Milky Way as evidence that the stratum 

 of stars is limited, and that here we can see beyond it. In fact, it would 

 appear that it is a very complicated question ; and as the zone itself is 

 complicated " with outlying branches beyond the range of our most powerful 

 telescopes," so an actual knowledge of the Milky Way is beyond us at 

 present. It is composed of most extraordinary aggregations of stars, which 

 appear not only impossible to count, but each one to be independent of the 

 other, Thus we must conclude our rapid survey of the Milky Way, and 

 close with Mr. Proctor's remark in his " Universe of Stars." " The sidereal 

 system," he says, " is altogether more complicated, altogether more varied 

 in structure than has hitherto been supposed. Within one and the same 

 region co-exist stars of many orders of real magnitude, the greatest being 

 thousands of times larger than the least. All the Nebulae hitherto dis- 

 covered, whether gaseous or stellar, irregular, planetary, ring-formed, or 

 elliptic, exist within the limits of the sidereal system. They all form part 

 and parcel of that wonderful system, whose nearer and brighter parts 

 constitute the glories of our nocturnal heavens." 



And a little reflection will show how true this is. Not very long ago 

 in the world's life the solar system was supposed to consist of one sun with 

 a few planets wandering around him. Then some more were found, and 

 they were called " satellites." For a long time man fancied he had reached 

 the " ultima thule" of astronomy in these depths ; but the whole idea was 

 changed when it was discovered that beyond Mars there lie the asteroids 

 and the host of bodies in this solar system which we cannot do more than 

 allude to. Then when we consider that this "sun" of ours, which we think 



