"While we are about it, look in the bottom of the closet, and see
if you find the right number of empty bottles."

The valet obeyed, and looked into the closet.

"There isn't one there."

"Just so," returned M. Lecoq. "This time, show us your heels for
good."

As soon as Francois had shut the door, M. Lecoq turned to Plantat
and asked:

"What do you think now?"

"You were perfectly right."

The detective then smelt successively each glass and bottle.

"Good again! Another proof in aid of my guess."

"What more?"

"It was not wine that was at the bottom of these glasses. Among
all the empty bottles put away in the bottom of that closet, there
was one--here it is--which contained vinegar; and it was from
this bottle that they turned what they thought to be wine into the
glasses."