Lough Foyle means the borrowed lake, for in old times there were two weird sisters dwelling beyond the Shannon, who were skilled in necromancy. And the elder sister said to the younger—

“Give me the loan of your silver lake, for I have none; and I promise to restore it to you next Monday.”

So the younger, being good-natured, rolled up the lake in a sheet and despatched it over hills and dales to her sister. But when the time came f............