In keeping with the many other passages in the novel in which Lenehan predicts (falsely) the winner of the day's Gold Cup horse race, he tells M'Coy in Wandering Rocks that he wants to "pop into Lynam's" to learn the odds on Sceptre. Lynam's bookmaking business appears nowhere in the 1904 Thom's Directory so it was probably a black market operation, possibly run out of a home. Judging by the walking path that Joyce describes for Lenehan and M'Coy in that chapter, it seems to be housed on or just off Temple Bar.

John Hunt 2022

  Photograph of a Dublin betting shop held in the Dublin City Council Archive, date unknown but no doubt later than 1904. Source:

  Alain Le Garsmeur's photograph of bookmaker Frank McConville at the Leopardstown races, probably in the early 1990s. Source: McCabe and Le Garsmeur, James Joyce: Reflections of Ireland.