Page:Astronomy for Everybody.djvu/121

Years of greatest and least frequency, past and future are as follows:

Another noteworthy law connected with the sun's spots is that they are not found all over the sun; but only in certain regions of solar latitude.
Fig. 18.—Frequency of Sun-spots in Different Latitudes on the Sun. They are rather rare on the sun's equator, but become more frequent as we go north or south of the equator till we get to fifteen degrees of latitude, north or south. From this region to twenty degrees the frequency is greatest; then it falls off, so that beyond thirty degrees a spot is rarely seen. These regions are shown in the accompanying figure, where the shading is darker