CH. xxxi. CLUSTERS AND NEBULM. 285 



bodies did not appear in the least more separated, even with 

 the largest telescopes, and these Herschel called nebula or 

 clouds, because he believed they were made up of mere 

 masses of matter which had not yet formed themselves into 

 stars. 



It was at this point that the grand thought forced itself 

 upon his mind that in these nebulae we might be looking 

 at the actual beginning of new worlds : and that the creation 

 of the different bodies of the universe was not begun and 

 finished long ages ago, but is even now going on under our 

 eyes. The nebulae he believed to be composed of star- 

 matter, out of which stars might be slowly forming, so as to 

 be first seen scattered like minute points in some of the more 

 hazy star-clusters, and then clearly visible, as in the ' bee- 

 hive' in the constellation Cancer. In those days Herschel 

 could get very few astronomers to believe in this idea, but 

 you will see in the history of the nineteenth century how the 

 discoveries of the spectroscope (see p. 339) have proved that 

 the light of some of the nebulae comes from incandescent 

 gaseous matter ; so that it becomes extremely probable that 

 Herschel was right, and that, in far distant space, star- 

 mist is forming into stars, and creating new suns to illumin- 

 ate the universe. 



The Motion of our Solar System through Space, 

 1783. The third and last theory which we can mention as 

 coming from Sir William Herschel is that of the motion of 

 our sun through space. In 1783 he showed from a study 

 of the astronomical catalogues of past centuries that the stars 

 do not stand in exactly the same places with regard to us as 

 they did in ages gone by, and that, therefore, either we or 

 they must be moving through space. Now, when everything 

 around you appears to be moving backwards, it is most 

 likely, to say the least, that it is you who are moving forwards, 



