THE BODIES OF SPACE, 



THEIR ARRANGEMENTS AND FORMATION. 



IT is familiar knowledge that the earth which we inhabit is a 

 globe of somewhat less than 8000 miles in diameter, being one 

 of a series which revolve at different distances around the sun, 

 and some of which have satellites in like manner revolving 

 around them. The sun, planets, and satellites, with the less 

 intelligible orbs termed comets, are comprehensively called 

 the solar system ; and if we take as the uttermost bounds of 

 this system the orbit of Uranus (though the comets actually 

 have a wider range), we shall find that it occupies a portion of 

 space not less than three thousand six hundred millions of 

 miles in diameter. The mind fails to form an exact notion of 

 a portion of space so immense ; but some faint idea of it may 

 be obtained from the fact, that, if the swiftest race-horse ever 

 known had begun to traverse it, at full speed, at the time of 

 the birth of Moses, he would as yet have accomplished only 

 half his journey. 



It has long been concluded amongst astronomers, that the 

 stars, though they appear to our eyes only as brilliant points, 

 are all to be considered as suns, representing so many solar 

 systems, each bearing a general resemblance to our own. The 

 stars have a brilliancy and apparent magnitude which we may 

 safely presume to be in proportion to their actual size and the 

 distance at which they are placed from us. Attempts have 

 been made to ascertain the distance in some instances by cal- 

 culations founded on parallax ; that is, the change of relative 

 situation produced on a heavenly object by our planet passing 

 from one part of its orbit to another exactly opposite ; it being 

 previously understood that if, upon this base of nearly two 

 hundred millions of miles, an angle of so much as one second, 

 or the 3600th part of a degree, could be raised, the distance 



B 



