The mender of roads, who represents what Dickens calls "the sea of time" or the revolution, is a "grizzled" man who joins the group around the fountain of the village after the Marquis callously runs over a small child and continues on his way to the chateau in Chapter 8 of Book the Second of A Tale of Two Cities. As the Marquis regards the "misery-worn face and figure" of a peasant, he notices the mender of roads in the blue cap: "Bring me hither that fellow!"
The Marquis d'Evremonde asks this man why he has looked so fixedly at his carriage when it passed him coming up the hill as well as at the top of the hill. The mender of roads says, "Monseigner, I looked at the man," pointing under the carriage. His vagueness in mentioning no name for the man raises the ire of the Marquis, who demands to know the name of the man who hung from the chains under his carriage, contending that the mender in the blue cap knows all the other peasants. However, the mender of roads declares,
"He was not part of the country. Of all the days of my life, I never saw him."
Continuing to respond to the aristocrat's questions, the mender of roads states that the man was covered with dust and was "white as a spectre, tall as a spectre!" After this statement, all eyes are on the Marquis, who is clever enough not to "ruffle such vermin." He compliments the man that he has done well in telling him. Then, he instructs Monsieur Gabelle, the Postmaster and tax functionary, to have this man watched and see that his dealings are not secretive. Gabelle is also instructed to investigate what has become of the man who hid under the carriage.
This mender of roads will appear later in the narrative as he is brought to the wine shop of the DeFarges where he shown both "dolls and birds" as Madame Defarge calls them; that is, he will see more aristocrats whose appearance and histories will influence him further in the "sea of time," the approaching fate of the revolution. His blue hat symbolizes this sea for the new revolutionary.
In Charles Dickens' novel, A Tale of Two Cities, the Marquis is annoyed with the mender of roads because the man saw someone hanging from a chain beneath the Marquis' carriagebut couldn't give enough information:
...the mender of roads with his blue cap pointing out the chain under the carriage...
The mender of the roads is not able to provide much of a description other than the "stowaway" had a face that was white and he was as tall as a spectre (ghost).
...to whom the mender of roads, with the aid of the blue cap without which he was nothing, still enlarged upon his man like a spectre, as long as they could bear it.
The Marquis, knowing little more than he had before the mender of roads made his report is disgusted with really knowing nothing more and having no way to understand the significance to himself of this mysterious man.
(However, as the story continues, it seems that the father of the little child the Marquis had hit and killed with his carriage is out of his mind with despair. The next morning, the Marquis is found dead.)
Later as a man has been captured for the murder of the Marquis, the mender of the roads provides, once again, a detailed account of what he saw:
“I saw him then, messieurs,” began the mender of roads, “a year ago this running summer, underneath the carriage of the Marquis, hanging by the chain. Behold the manner of it. I leaving my work on the road, the sun going to bed, the carriage of the Marquis slowly ascending the hill, he hanging by the chain—like this.”
It would seem the mystery of the man beneath the carriage has been answered—but not that it would be of any help to the Marquis.