Most holidays come with a calendar, a crowd and a fair amount of noise. Longfellow's sonnet begins by quietly overturning that idea. The "holiest" holidays, he says, are "kept by ourselves in silence and apart." They are "the secret anniversaries of the heart," occasions when "the full river of feeling overflows." The rest of the poem works out what such days might be, and the answer proves more wistful than the opening suggests.
The first eight lines are one rushing sentence, its items strung together with semicolons like a list that can't stop itself. We get "happy days unclouded to their close," "sudden joys that out of darkness start / As flames from ashes," and "swift desires that dart / Like swallows singing down each wind that blows!" The images move through water, fire and air, so feeling seems like something natural and uncontrollable: a flood, a spark, a flight. Not everything here is sunshine, either. Joys leap "out of darkness" and "from ashes," which hints that the happiest private moments are sometimes born from loss. The swallows are the best touch. They sing while riding the wind rather than fighting it, and so desire becomes something that travels with life's currents. The exclamation mark at the end of line 8 is the poem's only one, the crest of the wave.
The rhyme scheme is the Petrarchan pattern, ABBAABBA in the octave and CDECDE in the sestet. In the octave only two sounds return again and again: "those," "close," "overflows," "blows," and then "apart," "heart," "start," "dart." The word "heart" sits among words of sudden movement, as if the poem were rhyming the organ with its own leaps. The rhythm is steady iambic pentameter throughout. That evenness matters, because the surging emotion is held inside a calm, composed frame, much like the private room the poem describes.
At line 9 the poem turns, and the colour drains out. "White as" begins three lines in a row, each a new simile: a "receding sail," a cloud that "floats and fades in air," a lily on a stream. Compared with the flames and swallows of the octave, these are cooler, paler and quieter. Whiteness suggests purity, but two of the three images are really about vanishing, so the repeated word carries distance as well. Only now, in line 11, do we learn what has been described all along: "These tender memories are." The subject is held back until the feeling has been built up around it. The lily on the stream also quietly returns us to the river of line 4, now still instead of overflowing.
The last three lines let go of the real world altogether. The memories become "a fairy tale / Of some enchanted land we know not where," and the line break leaves "a fairy tale" hanging for a moment before it is explained. The old-fashioned "know not where" admits something true about memory: we can lose the address of our happiest days and keep only their feeling. The final line, "lovely as a landscape in a dream," is full of soft, liquid sounds, and it slows the poem to a close. The rhymes help here too. "Sail" and "tale" link a ship slipping from view with a story, and "stream" and "dream" link flowing water with the imagination.
What makes the poem worth reading is how much it does without a single specific memory. Longfellow, the nineteenth-century American poet, speaks in terms of "we" and "ourselves," so readers have to supply their own private days. It also resists easy sentiment. These holidays are precious, but they cannot be revisited or even located, and they are already turning into dream. The poem argues that our inner lives keep a separate calendar, and that its most important dates are the ones no one else can see. Fourteen quiet lines are enough to give the reader a small holiday of their own.