174 
HAROLD’S DISCUSSIONS. 
limb of the sun, also when they disappear on the 
western limb. But the opposite is true. 
Are the spots sheets of solid matter floating on a 
liquid surface of the sun ? We would hardly expect 
Fig. 88.—Spot as it appears at regular periods, while passing 
from the center to the western limb. 
such fragments to take the same general path around 
the sun. The spots are seen on either side of the 
sun’s equator in a zone about twenty degrees in width. 
Then, too, as in the case of clouds, the light part 
would be toward us when appearing and disap¬ 
pearing. 
Are these spots cavities in the sun’s surface ? If 
this were true, we might expect to see notches in the 
sun’s edge as the spots came on at the eastern limb. 
