A Tale of Two Cities is replete with imagery and motifs; in addition, Charles Dickens uses a couple of strong symbols:
THE BROKEN WINE CASK
As the people scramble to lap up the wine that flows through the streets of Saint-Antoine, squeezing rags dripping with the wine into the mouths of their babies and dipping cups into it for themselves, the scene is symbolic of the desperate hunger of the French during the setting of the Revolution.
Then, after they have drunk, some of the people with "cadaverous faces" have their faces stained with this red wine, stains that symbolize the blood that will be shed in the forthcoming revolution:
Those who had been greedy with the staves of the cask, had acquired a tigerish smear about the mouth and one tall joker so besmirched...scrawled upon a wall with his finger dipped in muddy wine lees--BLOOD.
The incessant knitting of Madame Defarge symbolizes the coldblooded vengefulness of the revolutionaries as Madame Defarge stealthily knits in the registry of names of those condemned to die. With a flower in her hair and "seeing nothing," Madame Defarge appears harmless in her knitting, but she is deadly as she really sentences to death those whose names she knits. Likewise, this knitting represents the sang-froid and bloodlust of the other revolutionaries, simple peasants who appear harmless, but rise up to massacre countless aristocrats.
The knitting also suggests a relationship between the vengeance of the peasants and fate. For, as in Greek mythology, the three sisters of fate knit and weave, controlling human life. At the executions, the peasant women sit and knit mechanically, just as the guillotine brings about the victims' fateful ends.
The grindstone, on which the blades of death are sharpened also represents the fateful end to those whom the revolutionaries have condemned. It also represents the "mill that grinds young people old."
THE MENDER OF ROADS
This character with his blue cap represents the fickleness of the crowds that cheer and then punish. The mender of roads has been encouraged to cheer the queen and the king as they pass so that they will not realize how dissastified the people are; later, the crowd releases Darnay only to have him rearrested.
THE STONE MARQUIS
The face on the chateau of the Marquis d'Evremond changes after his assassination and the stone has two dints in the nose just like those of the live marquis. This stone image represents the cold-heartedness of the First Estate, a corrupt social order, as they ignored the poor and hungry. No longer human, they are but stone.