Housman
From WikiPOBia
In The Thirteen Gun Salute, Patrick O'Brian cites without attribution the poem "Bells in the Tower", by A.E. Housman.
This mention was discussed in an article, which appeared in substantially the same form in the "Housman Society Journal 2002", Volume Twenty Eight, p. 106 (see http://www.housman-society.co.uk)
The article can be found at http://www.hmssurprise.org/Miscellany/BellsInTheTower.html