2 THE BODIES OF SPACE, 



instances by calculations 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 ex- 

 actly 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 might be assumed in that instance 

 as not less than 19,200,000 millions of miles! In the 

 case of the most brilliant star, Sirius, even this minute 

 parallax could not be found ; from which, of course, it was to 

 be inferred that the distance of that star is something beyond 

 the vast distance which has been stated. In some others, on 

 which the experiment has been tried, no sensible parallax 

 could be detected ; from which the same inference was to 

 be made in their case. We seemed thus to be left in a hope- 

 less state of ignorance regarding the measurements of the 

 sidereal unijyerse, as if it were such a question as man was 

 not destined ever to answer ; but at length, in our own time, 

 responses came from several points almost at once. By Pro- 

 fessor Henderson, it was ascertained that the star a of the 

 constellation of the Centaur, the third in brightness in our 

 heavens, but in reality a double star, and believed for various 

 reasons to be among those nearest to us, had a parallax of a 

 full second, from which it was inferred that the distance 

 was the vast sum of miles which has been stated. Afterwards, 

 Bessel assigned a parallax of thirty one hundredths of a 

 second to the double star 61 Cygni, placing it at a distance 

 nearly 670,000 times that of the sun.(') Such are but the 

 first steps we take in imagination amongst the hosts of orbs 

 by which we are surrounded. If we suppose that similar 

 intervals exist between all the stars, we shall readily see that 

 the space occupied by even the comparatively small number 

 visible to the naked eye must be vast beyond all powers of 

 human conception. 



The number visible to the eye is about three thousand ; 

 but when a telescope of small power is directed to the 

 heavens, a great number more come into view, and the 

 number is ever increased in proportion to the increased power 



