to make sure that she was
not being followed, and then took a cab and drove down the boulevard and
the Rue de la Pepiniere, to the Gare Saint-Lazare.

Don Luis saw her from a distance climbing the steps that run up from the
Cour de Rome; and, on following her, caught sight of her again at the
ticket office at the end of the waiting hall.

"Quick, Mazeroux!" he said. "Get out your detective card and ask the
clerk what ticket she's taken. Run, before another passenger comes."

Mazeroux hurried and questioned the ticket clerk and returned:

"Second class for Rouen."

"Take one for yourself."

Mazeroux did so. They found that there was an express due to start in a
minute. When they reached the platform Florence was stepping into a
compartment in the middle of the train.

The engine whistled.

"Get in," said Don Luis, hiding himself as best he could. "Telegraph to
me from Rouen; and I'll join you this evening. Above all, keep your
eyes on her. Don't let her slip between your fingers. She's very
clever, you know."

"But why don't you come yourself, Chief? It would be much better--"

"Out of the question. The train doesn't stop before Rouen; and I
couldn't be back till this evening. The meeting at the Prefect's is at
five o'clock."

"And you insist on going?"

"More than ever. There, jump in!"

He pushed him into one of the end carriages. The train started and soon
disappeared in the tunnel.

Then Don Luis flung himself on a bench in a waiting room and remained
there for two hours, pretending to read the newspapers. But his eyes
wandered and his mind was haunted by the agonizing question that once
more forced itself upon him: was Florence guilty or not?

* * * * *

It was five o'clock exactly when Major Comte d'Astrignac, Maitre
Lepertuis, and the secretary of the American Embassy were shown into M.
Desmalions's office. At the same moment some one entered the messengers'
room and handed in his card.

The messenger on duty glanced at the pasteboard, turned his head quickly
toward a group of men talking in a corner, and then asked the newcomer:

"Have you an appointment, sir?"

"It's not necessary. Just say that I'm here: Don Luis Perenna."

A kind of electric shock ran through the little group in the corner; and
one of the persons forming it came forward. It was Weber, the deputy
chief detective.

The two men looked each other straight in the eyes. Don Luis smiled
amia