Thames

SETTING THE THAMES ON FIRE, phr. (old).—A simile for the impossible: see quots.

  1363.  LANGLAND, Piers Plowman. C. vii. 335.

  [Wicked deeds fare as a spark of fire that falleth into the Thames.]

  1546.  HEYWOOD, Proverbs. ‘As well cast water in TEMS as give him alms.’

  1672.  RAY, Proverbs, ‘Joculatory Proverbs.’ I care no more for it than a goose-turd for the THAMES.

  1777.  FOOTE, The Trip to Calais, iii. [He] won’t SET FIRE TO THE THAMES.

  1785.  GROSE, A Classical Dictionary of the Vulgar Tongue, s.v. THAMES. He will not find out a way TO SET THE THAMES ON FIRE; he will not make any wonderful discoveries, he is no conjuror.

  1868.  BREWER, Dictionary of Phrase and Fable, s.v. THAMES. An active man would ply the TEMSE so quickly as to set fire to the wooden hoop at the bottom; but a lazy fellow would never SET THE TEMSE ON FIRE. The play on the word temse has given rise to many imitations: as, He will never set the Seine on fire (the French seine = a drag-net).

  1884.  Notes and Queries, 6 S., ix. 14 (Correspondent). To a practical man a grain-riddle firing would sound most absurd. If you say to a Lancashire labourer, ‘Tha’ll ne’er SET TH’ TEMS AFIRE,’ a hundred to one he would understand the River Thames. Ibid. (Editorial). The ordinarily accepted supposition is that it is equivalent to saying that an idle fellow will not accomplish a miracle.