The further resolvability of a great many double stars is perhaps the most curious result of modern improvements in the optical means of observing them. With every addition to the defining power of telescopes, the visible complexity of stellar systems has increased so rapidly as to inspire a suspicion that simple binary combinations may be an exception rather than the rule. The frequency with which what appeared to be such have yielded to the disintegrating scrutiny of Mr. Burnham and others, suggests at any rate the presence of an innate tendency, and seems to show that the duplicity of stars is no accident of nebular condensation, but belongs essentially to the primitive design of their organisation. Although we can never become fully acquainted with all the detailed arrangements of stellar systems, we are then led to suppose them far more elaborate and varied than appears at first sight. Each, we cannot doubt, is adapted by exquisite contrivances to its special end, reflecting, in its untold harmonies of adjustment, the Supreme Wisdom from which they emanate.

The continuance of the process of optical dissociation, begun by the splitting-up of an apparently simple star, sometimes shows the primary, sometimes the satellite, not unfrequently both primary and satellite, to be very closely double. Ternary systems are accordingly of two kinds. In one, the smaller star consists of two in mutual circulation, and concurrent revolution round a single governing body; in the other, an intimately conjoined pair guides the movements of an unattended attendant.