TIME FOR GAUGING THE HEAVENS 145 



studded with continents and islands of stars, which he 

 called nebulae, clusters, or groups. The Milky Way, 

 with its many millions of shining suns, is one of these 

 thickly peopled islands, separated from many others as 

 rich or perhaps richer of worlds, in this infinite ocean. 

 Of these nebulae or clusters, or star islands, he had, 

 up to that time, counted "more than 900, many of 

 which, in all probability, are equally extensive with 

 that which we inhabit ; and yet they are all separated 

 from each other by very considerable intervals. Some 

 there are that seem to be double and treble; and 

 though with most of these it may be that they are 

 at a very great distance from each other, yet we allow 

 that some such conjunctions really are to be found. 

 But then these compound or double nebulas still make a 

 detached link in the great chain." He fell from some 

 of these views at a later period, wholly or in part. 



Herschel delighted in these attractive speculations. 

 In a paper on the power of telescopes to penetrate 

 space, one of the conclusions he came to was that, 

 while his 20-feet reflector " might possibly have 

 reached to some distance beyond the apparent bounds 

 of the Milky Way," his 40- feet would reach stars 

 from which light would take about two millions of 

 years to reach our earth. A ray of light revealing to 

 us the history of stars as it was two millions of years 

 ago! If such things are dreams or miscalculations, 

 they soar into the sublimest regions of mortal thought. 

 More amenable to arithmetic is his calculation, that it 

 will require not less than 598 years, of 100 working 

 hours each, to take a census of the stars by looking 

 with his 40-feet "only one single moment into each 

 part of space, and, even then, so much of the southern 



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