in antiquity, sacrifices or ceremonies by which the ancients purified their cities, fields, armies, or people, defiled by any crime or impurity.

Some of these lustrations were public, others private. There were three species or manners of performing lustration, viz. by fire and sulphur, by water, and by air; which last was done by fanning and agitating the air round the thing to be purified. Some of these lustrations were necessary, that is, could not be dispensed with, as lustrations of houses in time of a plague, or upon the death of any person; others again were done out of choice, and at pleasure. The public lustrations at Rome were celebrated every fifth year, in which they led a victim thrice round the place to be purified, and in the mean time burnt a great quantity of perfumes.