marsh light

marsh light (plural marsh lights)

1. A will o' the wisp.
2. (figuratively) A delusion, a false hope.
   • 1886 October – 1887 January, H[enry] Rider Haggard, She: A History of Adventure, London: Longmans, Green, and Co., published 1887, →OCLC:

     "Thus, even thus, have I lived for full two thousand years - for some six and sixty generations, as ye reckon time - in a Hell, as thou callest it - tormented by the memory of a crime, tortured day and night with an unfulfilled desire - without companionship, without comfort, without death, and led on only down my dreary road by the marsh lights of Hope, which, though they flickered here and there, and now glowed strong, and now were not, yet, as my skill told me, would one day lead unto my deliverer."