Numbers 19:17

Burning of the red cow, which was also a sin-offering, ver. 9. (Haydock) --- Upon the ashes they poured some running or spring water. The pagans generally preferred the water of the sea; or if they could not procure any, they mixed salt with common water. Ovid (Fast iv,) mentions a lustration made with the ashes of a calf, mixed with horse blood; and another, which was used in honour of Pales, the goddess of harvests, by the oldest virgins present, who sprinkled the ashes of calves, populos purget ut ille cinis. Athenæus (ix. 18,) observes that a stick was taken from the fire of the altar, was extinguished in water for the purification of the unclean; and the ancient Romans, who had been at a funeral, sprinkled themselves with water, and jumped over fire for the same purpose; as the Greeks were accustomed to place a vessel full of water, at the doors where a corpse was lying, that all might purify themselves when they came out. (Calmet)