"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. Delcassé'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.