Apr. 
x THE STARRY HEAVENS 413 
earth’s orbit we can calculate the distance of 
the star. The difficulty is that the apparent 
ellipses are so minute that it is in very few 
cases possible to measure them. 
dan ‘ At 
Fig. 54,— The Parallactic Ellipse. 
The distances of the Fixed Stars thus tested 
are found to be enormous, and indeed gener- 
ally incalculable; so great that in most cases, 
whether we look at them from one end 
of our orbit or the other —though the dif- 
ference of our position, corresponding to the 
points marked January and July in Fig. 54, 
is 185,000,000 miles — no apparent change of 
position can be observed. In some, however, 
the parallax, though very minute, is yet ap- 
ta 
