232 HERSCHEL AND HIS WORK 



Neptune, to be filled with gas, luminous or not. It 

 would not occupy more than a fortieth part of the 

 space in the heavens occupied by the great nebula in 

 Orion, and it is doubtful if our best telescopes reveal 

 the whole of that nebula's extent in any direction. It 

 is within such vast spaces that Herschel imagined this 

 world-making process to be going on. Man's imagina- 

 tion quails in his attempt to grasp the space required 

 for such a workshop, the tools employed, or the time 

 taken to condense " nebulous matter " into dazzling 

 suns or dark companions. 



We are so much accustomed to feast our eyes on 

 drawings of a few magnificent and singularly shaped 

 nebulae, that thought is apt to overlook the vast 

 numbers of them scattered over the heavens in all 

 stages of size or progress. Herschel did not fall into 

 this mistake. His object was higher than to satisfy 

 curiosity or to excite wonder. He had the feeling that 

 there was a process going on, of which he believed he 

 could trace not a few of the stages. The smallest and 

 the least wonderful of the nebulae might thus prove to 

 be as important in tracing out this progress, as the 

 most awe-inspiring. Nor did he look upon all of them 

 as resolvable into stars or masses of shining matter, 

 more or less rare. He believed that some of them 

 were not luminous, but dark ; but he made no attempt 

 to explain, as may be at least attempted to-day, how a 

 vast mass of invisible gas may become lighted up, and 

 send its brightness off on a journey of ten or twenty or 

 fifty years, to publish to us the changes that, in process 

 of ages, had taken place in its nature. It was the dis- 

 covery of world-making he was aiming at in these long 

 and laborious, but not wearisome researches. Others 



