Time imparts order to the fluid thoughts, memories, and encounters that make up Mrs. Dalloway. Big Ben, a symbol of England and its might, sounds out the hour relentlessly, ensuring that the passage of time, and the awareness of eventual death, is always palpable. Clarissa, Septimus, Peter, and other characters are in the grip of time, and as they age they evaluate how they have spent their lives. Clarissa, in particular, senses the passage of time, and the appearance of Sally and Peter, friends from the past, emphasizes how much time has gone by since Clarissa was young. Once the hour chimes, however, the sound disappears—its “leaden circles dissolved in the air.” This expression recurs many times throughout the novel, indicating how ephemeral time is, despite the pomp of Big Ben and despite people’s wary obsession with it. “It is time,” Rezia says to Septimus as they sit in the park waiting for the doctor's appointment on Harley Street. The ancient woman at the Regent’s Park Tube station suggests that the human condition knows no boundaries of time, since she continues to sing the same song for what seems like eternity. She understands that life is circular, not merely linear, which is the only sort of time that Big Ben tracks. Time is so important to the themes, structure, and characters of this novel that Woolf almost named her book The Hours.