The color yellow is first connected with Blanchard’s hot-air balloon, which Matilda describes as “a yellow silk bubble escaping the earth” (4). This balloon is the color of the bright, life-giving sun as it represents Matilda’s hope to “slip free” (4) of the constraints in her life.

Once yellow fever overtakes Philadelphia, the color yellow becomes a negative symbol of disease and death. A yellow tinge to a sick person’s eyes means they’ve caught the deadly fever, as Matilda discovers when she sees her mother’s “cornflower blue eyes poisoned with streaks of yellow and red” (67). Yellow rags tied to doorways—“pus yellow, fear yellow” (118)—warn citizens away from buildings where the pestilence has invaded. The association of yellow with fear is particularly significant, as people choose to save themselves instead of helping their neighbors.

Once the fever dies with the frost, the color yellow is once again a positive symbol of hope. Recalling Blanchard’s balloon from the novel’s opening, Matilda watches “the yellow sun r[ise], a giant balloon filled with prayers and hopes and promise” (243). Like the sun itself, yellow becomes a symbol of new life and hope for Matilda and the people she loves.