They are universal on both sides of the globe; and from pole to pole the magnetic needle trembles during their continuance.

Some authorities are of opinion that these eleven-year cycles are subject to a larger cycle, but sun-spot observations have not existed long enough to determine this point.

For myself, I have a great difficulty in forming an opinion.

I have very little doubt that the spots are depressions on the surface of the sun.
This is more apparent when the spot is on the limb.

I have often seen the edge very rugged and uneven when groups of large spots were about to come round on the east side.