E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Draught of Thor (The).
The ebb of the sea. When Asa Thor visited Jötunheim he was set to drain a bowl of liquor. He took three draughts, but only succeeded in slightly reducing the quantity. On leaving Jötunheim, the king, Giant Skrymir, told him he need not be ashamed of himself, and showed him the sea at low ebb, saying that he had drunk all the rest in his thre \??\. We are told it was a quarter of a mile of sea-water that he drank.