Page:The Music of the Spheres.djvu/77

 W-shaped Chair of the unfortunate Queen Cassiopeia who sits in the Milky Way. Aratus, the Greek poet, claims that the sparkles of light which twinkle in this vicinity are particles of dust which the hero stirred up in his haste to rescue Andromeda.

What a charming picture to impress upon the sky!

But now in the twentieth century we analyze this dust which the ancients claim their Perseus raised—and what do we find? Every particle in that misty path is a mighty sun, suspended amidst multitudes of other mighty suns, massed in one long strip of splendor across the sky. For (calmly speaking) the Milky Way is a zone of innumerable stars so very distant that the individual lights are blended in one continuous band of silvery haze.

Against this glorious path stands Perseus, sword upraised among its stars, while entangled in the fearful locks of the Gorgon Medusa glows Algol, the "Blinking Demon." This so-called demon-star actually winks, that is, it indulges in one long, slow wink at intervals of exactly 2 days, 20 hours and 49 minutes. Such a phenomenon used to be a source of terror to the Arabs who feared it might be predictive of some disaster.

Although Perseus and the Gorgon are figments of fancy the wink of this amazing star is not imaginary by any means, for its light actually drops from the 2nd magnitude to the 4th magnitude and stays thus, half darkened, for about 20 minutes. Then it begins to slowly brighten and in the course of the next three hours regains its former brilliancy. In the clear air of the desert where the large stars burn like fire-brands, this change in brightness is very noticeable. Since it was not understood, it seemed terrifying and the superstitious Arabs imagined it to be the eye of a demon. It seemed a fitting star for the ancient Greeks to place on the