E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Footprints on the sands of Time (Longfellow: Psalm of Life). This beautiful expression was probably suggested by a letter of the First Napoleon to his Minister of the Interior respecting the poor-laws:It is melancholy [he says] to see time passing away without being put to its full value. Surely in a matter of this kind we should endeavour to do something, that we may say that we have not lived in vain, that we may leave some impress of our lives on the sands of Time.
To number sands. To undertake an endless or impossible task.