THE RANGE OF NATURE's OPERATIONS. 217 



The unit for the distances of satellites from their primaries is the 

 earth quadrant, the quadrant being 1,000 stages. 



The unit for the distances of planets from the sun is the metro-ten, 

 the metro-ten being 1,000 quadrants, which is the same as a million 

 stages. 



The unit for stellar distances is the metro-sixteen, the metro-sixteen 

 being a million metro-tens, or one billion stages. 



The position which the metro-sixteen, or billion stages, occupies is 

 indicated on the table. Light in the open ether takes 1.056 year 

 (nearl\' a year and three weeks) to travel a metro-sixteen, so that the 

 metro-sixteen is a little more than what in astronom}^ has sometimes 

 been called the ''"light ^^ear." 



The distances of the nearest stars, those few of which the parallax 

 can be directh' measured,^ fall within Aw, the subsection of smallest 

 stellar distances, as appears from the examples shown in fig. ,5. 



Thus Aw includes the distances of the nearest stars along with sub- 

 stellar distances; that is, distances from the sun to stations between the 

 solar system and the nearest star. Such substellar intervals probably 

 exist between the stars of a cluster. 



The farthest stars visible to us are probably less than 10,000 times 

 farther than the few whose parallax can be directly measured, since a 

 star sending us one hundred-millionth part of the light of Sirius would 

 probablv not be visible. 



If this view is correct Av, which is the middle subsection of Group 

 A, provides places to represent the distances of the stars visible to the 

 naked eye, along with all those which our telescopes can reach. 

 Accordingh', a sphere of which the radius is a metro-twenty, or some 

 two or three metro-twenties, would include our whole stellar universe. 

 Now, our table extends 1,000 times beyond the column of metro- 

 twenties, so that the greater part of sulisection Au makes provision 

 for measuring distances as much farther out than the most distant star 

 known to us, as a sphere with a mile for its radius ranges beyond a 

 concentric sphere, with less than a yard for its radius. 



It is just possible that the inner portion of this extension is necessary 

 to represent man's present knowledge; that, in fact, some of the non- 

 gaseous nebulte — e. g., the great Nebula in Andromeda — may l)e stellar 

 "universes" distinct from ours and located somewhere within the 

 larger sphere. If so, when we looked upon the speck of light which 

 brightened up in the Nebula of Andromeda a few years ago we mtiy 

 have been then actual spectators of an event which realh' happened 

 some hundreds of thousands of years ago, the waves of wireless teleg- 

 raphy which communicated the information to us having occupied the 

 whole of that immense time upon their swift journey. 



^ See footnote on page 211. 



