Among the letters published for the first time in Words in Air: The Complete Correspondence Between Elizabeth Bishop and Robert Lowell is a 1970 missive from Bishop. She is reading about Thomas Carlyle, she tells Lowell, and may try to "finish" a "poem about him I've had around for years." She never did finish it, however, and the poem is not exactly about "him." A draft appears posthumously as "Mr. and Mrs. Carlyle," and it narrates an incident taken from Jane Carlyle's correspondence, in which Thomas meets his wife in a busy street after missing her at "The Swan With Two Necks." Bishop's worksheets hail that place-name in what seems to be a final stanza, affirming the doubled bird as a symbol of the Carlyles' relationship---and the epistolary dynamics of that relationship in particular. Bishop suggests the "Swan With Two Necks" as a model of correspondence when she rewrites Jane's letter's anecdote about returning with the" mail from Liverpool" at a mail-coach inn.
Phillips, Siobhan. "Elizabeth Bishop and the Ethics of Correspondence." Modernism/modernity 19, no. 2 (2012): 343-363.