THE HERSCHELS AND THE STAR-DEPTHS. 21 



believed) than the stars seemingly immersed in it. In 

 reducing the distance of this object many hundreds of 

 times, Herschel was reducing its vastness many millions 

 of times. But then it is to be noted that in simply 

 ceasing to view this particular nebula as a vast external 

 system of suns, Herschel was by no means seeking to 

 show that no such systems of suns exist outside our 

 galaxy. On the contrary, all the arguments from ana- 

 logy, on which he had founded his belief in external 

 star-systems, remained unimpaired, as also did much of 

 the observational evidence. And now Herschel was 

 showing our galaxy as a much more wonderful scheme 

 than it had hitherto been supposed to be. For, accord- 

 ing to these new views, vast as has been the time 

 during which our galaxy has been in existence, it has 

 not yet completely formed itself into stars. Over vast 

 regions belonging to it, enormous masses of nebulous 

 matter are gradually condensing into stars, single, 

 double, or multiple. The imagination is wholly unable 

 either to conceive the duration of the time-intervals 

 which have been and will be occupied by these wonder- 

 ful processes, or to picture the stupendous nature of 

 those laboratories of our galaxy, in which its suns have 

 had their genesis. 



Nothing is more remarkable, perhaps, in the history 

 of scientific theories than the circumstance that while 

 Sir W. Herschel's theory of self-luminous vapour exist- 

 ing within the limits of the galaxy is very commonly 

 spoken of, the actual fact that he thus anticipated one 

 of the most remarkable discoveries of recent times, 



