The speaker looks back with wonder at lovers separated by oceans, who had to wait months for a letter to arrive by ship. The opening question, "How did they do it?", sounds half admiring and half baffled, as if patience on that scale is almost impossible for us to imagine. When the letter finally comes, the reader slows down with it, "parsing" every word, squeezing meaning out of each line because there is so little else to hold on to.
The poem then moves into images. Onion-skin paper is thin and fragile, yet the speaker compares it to "a bed of salt," which suggests something delicate but also sharp, maybe tinged with tears or longing. The cursive handwriting is likened to Jonah's gourd vine, which in the biblical story grows in a night. That comparison hints at how quickly a letter's comfort can spring up and how easily it could wither. The mood is tender, reflective, and a little wistful, with a quiet sense of how much waiting once shaped love.