This is from Wallace Stevens's "Thirteen Ways of Looking at a Blackbird:"
He rode over Connecticut in a glass coach.
Once, a fear pierced him,
In that he mistook
The shadow of his equipage
I used to find this verse puzzling. Its sense seems plain enough: a man, apparently a personage insulated from the world by his 'glass coach,' is suddenly spooked by his coach's shadow, which he mistakes for an impingement by Nature. Like Randall Jarrell's ball-turret gunner in his somewhat different glass enclosure, the man in the glass coach, "loosed from [his] dream of life," wakes up to the [imaginary] Real for a moment: his splendid isolation is exposed as the fragile contingency that it is. The diction of this verse enacts its subject: the bubble of the glass coach--its rotund artificiality heightened by the wonderfully orotund word 'equipage'--is perfectly deflated by that baldly declarative last line, with its nonspecific ordinary accidental blackbirds.
"Thirteen Ways of Looking at a Blackbird" is an austere and tough-minded poem, which aims to show us the distance between the Real and the rationalized, predictable world we pretend we live in. But what is a 'glass coach' doing there? At a stretch, one might locate it in the borderland between reality and fable--in actuality, 'glass coach' refers to the kind of coach of state in which kings are conveyed to their coronations--but of course its richest associations are to fairy-tales. Stevens's character seems a 'practical' fellow, whose coach seems to tell us that "his state is kingly," and who "rode over Connecticut" like T. S. Eliot's "Cousin Nancy," who "Strode across the hills and broke them,/ Rode across the hills and broke them." Cinderella's coach seems an unlikely conveyance for such a man. But Wallace Stevens, that tough-minded insurance company executive from Hartford, Connecticut, though fanciful in his images, rarely stooped to whimsy. Why would he invent a glass coach riding over Connecticut?
Decades after college, when this question first niggled at me, I learned the answer. I was traveling from Boston to New York, seated on the shady (landward) side of the train, where it runs along Long Island Sound towards Stamford, Connecticut. The railway carriage had large windows on both sides, and the sun, near eleven o'clock, shone right through the train, casting a diaphanous shadow on the ground along my side of the track. Probably I was wool-gathering or had just looked up from a book; anyway, I was gazing unfocusedly out the window. Abruptly I was startled into alertness with my heart racing: rushing smoothly along, the shadow of my coach had passed over some brush by the track, and sudden twiggy blotches of shade had leapt up at me. Blackbirds!
When I thought about writing this, I expected to end with that image. This morning however, while I was Googling 'glass coach,' with my head full of the memory of those shadows beside the train, a sudden summons fetched me to my mother-in-law's backyard, where a large flock of grackles wheeled through a stand of leafless trees for ten or fifteen seconds; I gaped at them in amazement with the sun at my back. For an instant, two times were superimposed: the birds' shadows on the branches were indistinguishable from the shadow of a coach...