The Heavens in July. 
By Professor Samuel G. Barton of the University of Pennsylvania. 
I F we continue the arc formed by the 
stars in the handle of the big dipper 
in Ursa Major we follow a stream 
of stars in Bootes to the brilliant red 
star, Arcturus, at A. A further exten- 
sion of the same arc leads us to another 
bright star, Spica of Virgo, at B. 
Some months ago actual measurement 
The result showed that Arcturus was 
19,000,000 miles in diameter and its vol- 
ume roughly 11,000 times that of the 
sun. As these results were much more 
difficult to obtain than those upon 
Betelgeux the achievement is more re- 
markable. They indicate, however, that 
there are but few stars whose diameters 
NO (STM 
Figure 1. The constellations at 9 P. M.. July 1. (Hold the map so that the direction faced is at the 
bottom; that is, if facing east hold east at the bottom as south now is.) 
showed that the diameter of Betelgeux 
or Alpha Orionis was 300,000,000 miles. 
The second application of the same 
method was to the star Arcturus which 
was supposed to be the second largest 
star but much smaller than Betelgeux. 
are large enough to be found by these 
methods. 
If we draw a line from north to south 
on our map we find that it passes 
through the serpent constellations. 
Lowest in the south is the well marked 
