1. A globe of glass filled with water, used to collect and throw the rays of light upon an object.
1665. Hooke, Microgr., 53. Ibid., 181. The Eggs of Silkworms … afford a pretty Object for a Microscope … especially if … the light of a window be cast or collected on it by a deep Convex-glass, or Water-ball.
2. Hour water-ball [after hour-glass], a contrivance for measuring time by the rising and sinking of a ball in water.
1655. Marq. Worcester, Cent. Inv., Index, An Hour Water-ball.
3. (See quots.)
1696. R. H., Sch. Recreat., 30. A Fire that will burn in the Water, or Water Ball.
1799. G. Smith, Laboratory, I. 43. Water-balls, or globes, made of wood, which swim and burn upon the water.
