All three groups were distinguished by the remarkable
manner in which they moved about on the solar surface, not
only in longitude but also in latitude.
The first group moved forward 5°"2 in longitude, and o 0 ·6
upward in latitude, in· the four days following its formation.
In the fortnight that it was on the further side of the Sun
it moved forward 4°"0 in longitude, and 1°"1 downward in
latitude. It was no'Y a single circular spot, and remained nearly
stationary till its disappearance.
The second group, that of June 16, the principal group of
the year, showed the most extraordin,ary drift, as the first
diagram will show.
Some of the minor irregularities are probably due to faculous
or photospheric mat,ter drifting above portions of the group
and concealing certain di.stricts of it, revealing them again
by their witharawal later on. But as for the greater part of
its history, tbe group practically consisted of but one welldefined circular 
spot, there can be no doubt that the apparent
change of place from day to day corresponds very closely to
the real movement of the centre of the group upon the
solar surface. In this and in the second diagram the observed
positions for the first and last days at each appearance are not
given, as only a portion of the group was visible on some of
those occasions, and the centre of the part observed was therefore
not the true centre of the group.

The third group of long duration, that of August z, was a very
perfect example, of the type above described. The first faint
spots were seen on .August 2. By August 4 the long stream of
spots with a large spot at either end had fully formed ; and by
August I 1 the leader alone remained. During the next rotation
the group consisted only of one large circular well-defined spots.
At its third appearance this circular spot was preceded by a
number of small spots, but. after September 26 the entire group,
and especially the smaller spots, began to diminish, and the
group had disappeared before reaching the west limb. The most
striking feature in ·the history of the group was the rapid backward drift 
shown after its first appearance The forward move ..
ment during the· first: rotation, the r~t.rogression whilst on _the