What is the symbolism of the leather satchel found by Elodie in the novel, The Clockmaker's Daughter?

For Elodie, the leather satchel serves as a symbol of both mystery and love. When she initially finds the satchel with the sketchbook and woman’s photograph inside, it represents a mystery she wants to solve. Elodie wants to discover who the satchel belonged, and the identity of the woman in the picture. Later, when Birdie gives the satchel to Edward as a gift, it symbolizes her love for him.