Mercurial BALLS, in pharmacy, are an amalgam of mercury and tin, sufficiently solid to be moulded, and to preserve a given form. The method of making them is by adding mercury to melted tin, and pouring the fluid mass into a round hollow mould.—These balls are employed to purify water, in which they are boiled; for which purpose travellers often carry some along with them. Nothing, however, can be more pernicious than such a practice, should the water contain any nitrous acid, which it very often does.
BALLS of Silk-worms and Spiders, are little cases or cones woven of silk, wherein those insects deposit their eggs. Spiders are extremely tender of their balls, which they carry about with them, adhering to the papillæ about
allaghan about their anus. Grew mentions balls or bags of a species of silk-worms in Virginia, as big as hens eggs, and containing each four aurelias.
Zoologists speak of a sort of balls of hair covered over with a smooth shining coat, or shell, found in the stomachs of oxen, cows, calves, horses, sheep, and goats. See the article BEZOAR.