go inside!” I hurried by Perrin and through the cool, quiet hall to the broad door that opened into the big room at the back of the house, which was Vic’s laboratory.

Vic! Hope!” I pounded as hard as I could, shouting their names. There was no response.

“Is there another key, Perrin?” I snapped.

“No, sir; none that I know of. The master was mighty fussy about his workroom.”

“Can we get in through the windows?”

“No. They’re barred, if you remember rightly, and fitted with this frosted glass, so you can’t see in, even.”

“Then get me an ax!” I commanded. “Quick!”

“An ax?” hesitated Perrin.

“An ax—and be quick about it!”

Perrin mumbled a protest and hurried away. I turned to Mrs. Perrin, who had come up to determine the result of my shouting.

“How long is it since Miss Hope went in there?”

“How long, sir? I’d say about twenty minutes before you came. Maybe twenty-five. I wasn’t paying any particular attention, sir. She just got the key and went in. After a few minutes I heard something buzzing in there, and I thought maybe Mr. Butler was showing her some new gadget of his, like he was always doing. Then there was a telephone call for him, and I couldn’t make neither of them answer; that’s when Mr. Perrin and I began to get worried.”

“I see.” Perrin came hurrying up with the ax, and I motioned them aside. I swung the ax, and the head of the weapon crashed against the lock. The knob dropped to the floor with a clatter, but the door gave not at all.

I brought the ax down again, and something cracked sharply. The third blow sent the door swinging wide.

Cautiously,