176 
HAROLD’S DISCUSSIONS. 
the sun is a dark, possibly solid, sphere surrounded 
by a burning envelope of gaseous matter. The envel¬ 
ope is called the photo or light sphere. The spots 
are openings in the photosphere through which we 
can see the dark body of the sun. 
This theory is further corroborated by other 
appearances on the surface. Careful observers, with 
fine glasses, have noticed that the surface of the sun 
is not smooth and of uniform color, as it appears to 
the eye. This appearance has been described by 
comparing it to willow leaves ” or ‘‘ rice grains,” 
arranged, more or less, in rows or bands. They 
appear somewhat more numerous and distinct near 
the center of the disk. They have been called faculi, 
which means torches, as they suggest fiames leaping 
up into the sun’s atmosphere. 
Some have thought that the spots are storm cen¬ 
ters in the photosphere. Occasionally, but not often, 
there has been noticed a spiral form, as if a cyclone 
prevailed. Though these spots sometimes move in¬ 
dependently of the sun’s surface, yet they appear too 
regular to regard them as cyclones in the photosphere. 
The fact that they occur in some zones, nearly corre¬ 
sponding to our trade-wind belts, seems to be in favor 
of the storm theory. In connection with eclipses, 
observers have often seen bright streams of light fiash 
out as if fiames of gas, chiefiy hydrogen, shot out 
from the sun to a great distance. (See Fig. 84.) 
The spots are often of immense size. In 1858, 
the largest one yet observed had a length of more 
than 140,000 miles. The great spot of 1883 was 
