384 
ASTRONOMY: G. E. HALE 
From this summary it appears that the five preceding spots observed 
in the northern hemisphere before the minimum were characterized by 
the violet component, while the single following spot gave the red com- 
ponent. In the southern hemisphere, with two exceptions, the polari- 
ties were of the opposite sign. 
After the minimum, to my surprise, the polarities were found to be 
reversed in both hemispheres, as the tabulated results for the new cycle 
indicate. The explanation of this fact probably lies in the change of 
latitude which a new cycle introduces. While the last spots of the old 
cycle appear in low latitudes, the first spots of the new cycle occur 
N 
S 
much farther from the equator. Thus we apparently have on the sun 
two spot zones, in which the great majority of spot vortices rotate in 
opposite directions. The approximate mean latitudes of these zones are 
shown in Table 2. 
From the best supplementary evidence at present available, the true 
direction of rotation of a preceding spot vortex in the low latitude zone 
is counter-clockwise, corresponding to that of a terrestrial tornado. 
The opposite direction obtains in the southern hemisphere, as on the 
earth. But in high latitudes the signs are reversed — a result which is 
hkely to prove significant in future studies of the sun (see figure) . The 
complete details of this investigation will be pubHshed in the Astrophysical 
Journal. 
