He glanced at the illuminated clock on the dashboard.
“We’re in nice time,” he commented. “Come along, Inspector; and the less said the better.”
They reached the door of Ravensthorpe exactly at one o’clock. Cecil was waiting for them on the threshold.
“Switch off those lights,” Sir Clinton said in a whisper, pointing to the hall lights which Cecil had left burning. “We mustn’t give the show away if we can help it. Someone might be looking out of a window and be tempted to come down and turn them out. You’re supposed to be in bed, aren’t you?”
Cecil nodded without speaking, and, crossing the hall, he extinguished the lamps. Sir Clinton pulled an electric torch from his pocket.
“There’s a staircase giving access to the servant’s quarters, isn’t there?”
Cecil confirmed this, and Sir Clinton turned to the Inspector.
“Which of your men is on duty at the museum door tonight?”
“Froggatt,” the Inspector answered.
“We’ll go along to him,” said Sir Clinton. “I want you, Cecil, to take the constable and post him at the bottom of that stair. Here’s the flash-lamp.”
Froggatt was surprised to see the party.
“Now, Froggatt,” the Chief Constable directed. “You’re to go with Mr. Chacewater. He’ll show you where to stand. All you have to do is to stick to your post there until you’re relieved. It’ll only be a matter of ten minutes or so. Don’t make the slightest sound unless anything goes wrong. Your business is to prevent anyone getting down the stair. There’ll be no trouble. If you see anyone, just shout: ‘Who’s there?’ That’ll be quite enough.”
The Inspector and Sir Clinton waited on the threshold of the museum until Cecil came back.
“Very convenient having these museum lights on all night,” Sir Clinton remarked. “We don’t need to muddle about with the flash-lamp. Now just wait here for a moment, and don’t speak a word. I’m going upstairs.”
He ascended to the first floor, entered Foss’s room and picked up the otophone, with which he returned to his companions.
“Now we can get to work,” he whispered, leading the way into the museum. “Just lock that door behind us, Inspector.”
Followed by the other two he stepped across the museum to the bay containing the safe. There he put the otophone on the floor and opened the case of the instrument. From one compartment he took an earphone with its headband. A moment’s search revealed the position of the connection, and he plugged the earphone wire into place in sockets let into the outside of the attaché case. A little further examination revealed a stud beside the leather handle, and this Sir Clinton pressed.
“That should start the thing,” he commented.
He lifted the hinged metal plate slightly and peered into the cavity which contained the valves.
“That seems all right,” he said, as his eye caught the faint glow of the dull emitters.
Shutting down the plate again, the Chief Constable put his finger into the compartment from which he had taken the earphone, pressed a concealed spring, and pulled up the floor of the compartment.
“This is the microphone,” he explained, drawing out a thick ebonite disk mounted on the false bottom of the compartment. “It’s attached to a longish wire so that you can take it out and put it on a table while the case with the valves and batteries lies on the floor out of the way. Now we’ll tune up.”
He brought microphone and earphone together, when a faint musical note made itself heard. Then he handed the microphone to Cecil.
“Hold that tight against the safe door, Cecil. Get the base in contact with the metal of the safe and keep the microphone face downwards. It’s essential to hold it absolutely steady, for the slightest vibration will put me off.”
He fitted on the headband and moved the two tiny levers of the otophone until the adjustment of the instrument seemed to satisfy him. Then, very cautiously, he began to work the mechanism of the combination lock. For some time he seemed unable to get what he wanted; but suddenly he made a slight gesture of triumph.
“It’s an old pattern, as I thought. There’s no balanced fence arbour. This is going to be an easy business.”
Easy or not, it took him nearly a quarter of an hour to accomplish his task; for at times he obviously went astray in the work.
“Try to keep your feet still,” he said. “Every movement you make is magnified up to the noise of a pocket avalanche.”
At last the thing was done. The safe door swung open. Sir Clinton took off the headband, received the microphone from Cecil, and packed it away in the case of the otophone along with the earphone.
“You’d better jot down the number of the combination, Cecil,” he suggested. “It’s on the dial at present.”
While Cecil was busy with this, the Chief Constable switched off the otophone and put it in a place of safety.
“Now we’ll see what’s inside the safe,” he said.
He swung the door full open and disclosed a cavity more like a strongroom than a safe.
“Have you any idea where the medallions were usually kept?” he inquired.
Cecil went over to one of the shelves and searched rapidly.
“Why, there are only two of them here!” he exclaimed in dismay.
“Hush!” Sir Clinton warned him sharply. “Don’t make a row. Have a good look at the things.”
Cecil picked up the medallions and scanned them minutely. His face showed his amazement as he turned from one to another.
“These are the replicas! Where have the genuine Leonardos gone?”
“Never mind that for the present. Put these things back again. I’m going to close the safe. We mustn’t risk talking too much here; and the sooner we’re gone the better.”
He picked up the otophone and led the way out of the museum.
“You might bring Froggatt back to his post here,” he said. “We don’t need him at the stair any longer. I must go upstairs again for a moment with this
