CH. xxx. STAR-CLUSTERS AND NEBULA. 275 



Cancer, were simply clusters of stars which might be seen 

 distinctly through a telescope. In others the separate 

 stars could not be seen even with the strongest magnifying 

 power, but the group looked so much more distinct through 

 a powerful telescope than through a feeble one, that it seemed 

 most likely the stars were there, if only they could be dis- 

 tinguished. But a third set of cloudy bodies did not appear 

 in the least more separated, even with the largest telescopes, 

 and these Herschel called nebultz, 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 

 discoverers of the spectroscope (seep. 3 2 7) have proved that 

 some of the nebulae are made of 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 illuminate the universe. 



The Motion of our Solar System through Space, 1783. 

 The third and last theory which we can mention as coining 

 from Sir William Herschel is that of the motion of our sun 

 through space. In 1783 he showed from a study of the 



