The names of three of the five stars forming the “Chair” are: Alpha (α) Schedar (from _Al Sadr_, the “Breast”); Beta (β) Caph (Arabic _Kaff_, “Hand”); and Delta (δ) Ruchbah or Rucbar, the “Knee.” Caph and Ruchbar are of particular interest, the first because, together with Alpheratz and Gamma Pegasi (often called Algenib, although that name belongs to Alpha Persei), it lies almost exactly on the Equinoctial Colure, or First Meridian of the Heavens; and Ruchbah, because, as explained in Chapter I, it lies in a line with Polaris and the true pole, thus serving to indicate the position of Polaris with regard to the pole at any time. Caph, Alpheratz, and Gamma Pegasi are often called the “Three Guides,” because, as just explained, they graphically show the line of the Equinoctial Colure, which is a great circle passing through the pole and cutting the equator at the Vernal and Autumnal Equinoxes. On the opposite side of the pole this line passes between the stars Gamma (γ) and Delta (δ) in Ursa Major. The star Eta (η) is an extremely beautiful binary, period about two hundred years, distance at present more than 6″. The combination of colors is especially remarkable, the larger component being orange, and the smaller purple. Piazzi Smyth saw the color of the smaller star as “Indian red,” and others have variously called it “garnet,” “violet,” and, curiously enough, considering the general opinion to the contrary, “green.” There is no doubt, whatever the exact hue may be, that this star wears a livery distinguishing it from any other in the sky. It is hardly an exaggeration to say that there is as great a variety of color tones among stars as among flowers. Although the great majority of stars approximate to white, there are, nevertheless, red stars, green stars, blue stars, lilac stars, yellow stars, orange stars, indigo stars, and violet stars, and stars of other tints and shades. All of those which are deeply colored are linked together in close pairs, but the colors they exhibit are not an effect of contrast. It is wonderful to think of _suns_ of such hues, but _there they are_! And, after all, it would be no more difficult to account for the colors of stars than for those of flowers. But to live under a purple or an emerald sun might not be as agreeable as life in the rays of our white orb, whose light splits into rainbows, as light of a single primary color could not do. A flower-garden under a green sun would not be the marvel of prismatic hues that it is in our world.[1]