The Egyptians used to say that the swelling of the Nile was
caused by the tears of Isis. The feast of Isis was celebrated at the
anniversary of the death of Osiris, when Isis was supposed to mourn for
The hero of the Nile.
Horatio, Lord Nelson (1758-1805).
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894