e know of, taking a circuitous route, loitering on the
way, and making certain that I am not followed. If I find myself
followed, I will pass this shop, dropping my handkerchief in front of
it and then turning back to pick it up. If I am not followed, I enter
the other house, mount to the roof and make sure that everything is in
order. At ten minutes to twelve, I hoist into place the two arms to
which our wires are secured, stretching them tight by means of the winch
which we have provided, and then I at once start the clockwork. I then
descend, make my way to the tram-station, and take a third-class ticket
to Colmar, where I will await you at Valentin's cabaret. If you do not
arrive by sundown, I am to go on to Paris to make my report."

"That is right. You have your passport?"

"Yes."

"Let me see your watch."

They compared watches and found that they both showed twenty minutes
past ten.

"Adieu, then," said the elder man; "and let there be no failure."

"Trust me, General!" and the Lieutenant saluted and went out through the
shop.

"And now, M. Vard," said Marbeau, in a low tone, "the hour has come."

The old man nodded, and together they left the room. Marbeau stopped to
secure the door, then followed Vard up to the first landing, where there
was another heavy door, which the Frenchman also bolted; so with the
next landing and the next. He smiled grimly as he thought of M.
Delcasse's warning to leave open a road of escape! He had, indeed,
provided such a road, but he carried it in his pocket.

At last they stood in a tiny room under the ridge of the roof. It was
lighted by a single dormer, and, looking out through this, one could see
over the house-tops, half a mile away, the grim wall of the arsenal.
Before the dormer stood a table, to which was bolted a metal framework,
supporting the box, with its sides of glass half-covered with tin-foil.
It was mounted on a pivot, and from it two heavy wires ran to a key such
as telegraphers use, and then down to a series of powerful batteries
standing on the floor.

"You are sure it is all right?" asked Marbeau, almost in a whisper.

For answer, Vard closed a switch, opened the key and then depressed it
slowly. There was a crackle of electricity, and a low humming like that
of a giant top.

"No, no!" gasped Marbeau, and snatched the switch open.

The inventor smiled.

"There is no danger," he said, "until the other current is turned on."

Marbeau's face was