Definition of "sponging"

I'm to be a poor, crawling beggar, sponging for rum, when I might be rolling in a coach!

1881–1882, Robert Louis Stevenson, Treasure Island, London, Paris: Cassell & Company, published 14 November 1883

I have employed cold air, and very often spongings with cold water, in order to moderate the preternatural heat of the skin, and to check the increased velocity of the circulation.

1815, William Shearman, New Medical and Physical Journal