Bailey's beads, dots of light on the edge of the moon seen in a solar eclipse, caused by the moon's inequalities of surface.
Base line, [68].
Biela's comet, [129].
Binary system, a double star, the component parts of which revolve around their centre of gravity.
Bode's law of planetary distances is no law at all, but a study of coincidences.
Bolides, small masses of matter in space. They are usually called meteors when luminous by contact with air, [120].
Celestial sphere, the apparent dome in which the heavenly bodies seem to be set; appears to revolve, [3].
Centre of gravity, the point on which a body, or two or more related bodies, balances.
Centrifugal force (centre fleeing).
Chromolithic plate of spectra of metals, to face [50].