Usage of à pas: where is the negation?

Question

In this passage from Le Horla (Guy de Maupassant), I fail to understand the usage of à pas:

Tout à coup, j’ai senti qu’il était là, et une joie, une joie folle m’a saisi. Je me suis levé lentement, et j’ai marché à droite, à gauche, longtemps pour qu’il ne devinât rien ; puis j’ai ôté mes bottines et mis mes savates avec négligence ; puis j’ai fermé ma persienne de fer, et revenant à pas tranquilles vers la porte, j’ai fermé la porte aussi à double tour. Retournant alors vers la fenêtre, je la fixai par un cadenas, dont je mis la clef dans ma poche.

The translation I found goes like this:

All of a sudden, I felt that he was there, and a joy, a mad joy seized me. I rose up slowly and paced back and forth, for a long time, so that he wouldn’t guess anything was amiss; then I took o# my shoes and nonchalantly put on my slippers; then I closed the iron shutters, and, quietly walking to the door, closed it too with a double turn of the lock. Then I came back to the window, locked it with a padlock, and put the key in my pocket.

What is happening here? Thank you!

Answer 1

There is no negation in this sentence.

Pas simply means "step" here so revenant à pas tranquilles means "walking back quietly" i.e. with "quiet steps".

Note that the second part of the splitted negative ne pas originally used to have this very same meaning (step) in ancient French so je ne marche pas literally means "I walk no step", i.e. I don't walk a step.

Similarily je ne recule (old French) that used to mean je [ne] recule pas (modern French) was often reinforced in je ne recule pas (old French) that we would write today: je [ne] recule pas d'un pas.