Other objects in Gemini that we can ill miss are: , double, magnitudes three and eleven, distance 73", p. 76 deg., colors yellow and blue; 15, double, magnitudes six and eight, distance 33", p. 205 deg.; gamma, remarkable for array of small stars near it; 38, double, magnitudes six and eight, distance 6.5", p. 162 deg., colors yellow and blue (very pretty); lambda, double, magnitudes four and eleven, distance 10", p. 30 deg., color of larger star blue--try with the five-inch; epsilon, double, magnitudes three and nine, distance 110", p. 94 deg.. From Gemini we pass to Cancer. This constellation has no large stars, but its great cluster Praesepe (1681 on map No. 4) is easily seen as a starry cloud with the naked eye. With the telescope it presents the most brilliant appearance with a very low power. It was one of the first objects that Galileo turned to when he had completed his telescope, and he wonderingly counted its stars, of which he enumerated thirty-six, and made a diagram showing their positions. The most interesting star in Cancer is zeta, a celebrated triple. The magnitudes of its components are six, seven, and seven and a half; distances 1.14", p. 6 deg., and 5.7", p. 114 deg.. We must use our five-inch glass in order satisfactorily to separate the two nearest stars. The gravitational relationship of the three stars is very peculiar. The nearest pair revolve around their common center in about fifty-eight years, while the third star revolves with the other two, around a center common to all three, in a period of six or seven hundred years. But the movements of the third star are erratic, and inexplicable except upon the hypothesis advanced by Seeliger, that there is an invisible, or dark, star near it by whose attraction its motion is perturbed. In endeavoring to picture the condition of things in zeta Cancri we might imagine our sun to have a companion sun, a half or a third as large as itself, and situated within what may be called planetary distance, circling with it around their center of gravity; while a third sun, smaller than the second and several times as far away, and accompanied by a _black_ or non-luminous orb, swings with the first two around another center of motion. There you would have an entertaining complication for the inhabitants of a system of planets! Other objects in Cancer are: Sigma 1223, double star, magnitudes six and six and a half, distance 5", p. 214 deg.; Sigma 1291, double, magnitudes both six, distance 1.3", p. 328 deg.--four-inch should split it; iota, double, magnitudes four and a half and six and a half, distance 30", p. 308 deg.; 66, double magnitudes six and nine, distance 4.8", p. 136 deg.; Sigma 1311, double, magnitudes both about the seventh, distance 7", p. 200 deg.; 1712, star cluster, very beautiful with the five-inch glass. [Illustration: MAP NO. 5.]