78 SCENERY IN A PATCH 



scattered through those territories of the universe that are 

 accessible to our gaze ; and could we be removed to any 

 of them, the whole of that great scheme of existence cir- 

 cumscribed by the Milky Way, might seem compressed 

 into a small globular patch in space, the aspect presented 

 by the nebulce to ourselves. The term nebula, signifying a 

 cloud or mist, is a denomination given to spots of pale light, 

 which are sprinkled in the heavens, a few of which may be 

 detected by the unaided eye. They vary considerably in 

 shape, size, and luminosity ; and occur in numbers, which 

 every improvement of the telescope increases. 



It was one of the great tasks of Sir William Herschel to 

 gauge the heavens, and to ascertain the relative distances of 

 the resolved and resolvable clusters ; and, as many of those 

 views which were deemed wild and visionary by his com- 

 peers, have, since his day, been triumphantly established, his 

 inquiries and conclusions in general are entitled to attention 

 and confidence. To the centres of the easily resolved sphe- 

 rical nebulae of the largest diameter, he assigned a remote- 

 ness 400 times that of Sirius. Those of half their diam- 

 eter, whose stars appear to be more closely wedged, he 

 supposed to be double the distance of the former ; and at 

 four times their distance, or 2400 times more remote than 

 Sirius, he placed those clusters which plainly indicate resolva- 

 bility, but whose components are not with our present means 

 apprehensible. In the last case we have an extent of space 

 equal to at least 45,000,000,000,000,000, or forty-five thou- 

 sand billions of miles. The dumb-bell nebula is certainly 

 not within that range, and probably much farther off. Light, 

 which comes to us from the sun in eight minutes flashing 

 along at the immense rate of 190,000 miles in a second of 

 time, or nearly twelve millions of miles in a minute, would 

 require upwards of seven thousand years to perform its 

 passage across the gulf! But Herschel went to a still 

 more tremendous depth in space that of 35,175 times the 



