tion leads to the formation of planets let us say a word or two more about these spots. They were discovered, so far as Western peoples are concerned, by Galileo in 1610.

Fig. 57.—Composite drawing of a Sunspot from several Greenwich photographs. The Chinese had noticed some of the large ones which can be seen with the naked eye from A.D. 188 onwards, but we had no knowledge of them at all till Galileo's time. Undoubtedly they are regions of fierce disturbance. Even in the old days, when Galileo first found them, the notion of disturbance or conflagration suggested itself, as