E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Prophesy upon Velvet (To).
To prophesy what is already a known fact. Thus, the issue of a battle flashed to an individual may, by some chance, get to the knowledge of a “sibyl,” who may securely prophesy the issue to others; but such a prediction would be a “prophecy on velvet;” it goes on velvet slippers without fear of stumbling.
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“If one of those three had spoken the news over again … the old lady [or sibyl] prophesies upon velvet.”—Sir W. Scott: The Pirate, ch. xxi.
