"Tread as lightly as you can," he said. "We are just making an exposure."
The attendant turned back with his lantern, and we followed Jervis into the room from whence he had come. It was a large room, and little lighter than the galleries, for the single glow-lamp that burned at the end where we entered left the rest of the apartment in almost complete obscurity. We seated ourselves at once on the chairs that had been placed for us, and, when the mutual salutations had been exchanged, I looked about me. There were three people in the room besides Jervis: Thorndyke, who sat with his watch in his hand, a gray-headed gentleman whom I took to be Dr. Norbury, and a smaller person at the dim farther end—undistinguishable, but probably Polton. At our end of the room were the two large trays that I had seen in the workshop, now mounted on trestles and each fitted with a rubber drain-tube leading down to a bucket. At the farther end of the room the sinister shape of the gallows reared itself aloft in the gloom; only now I could see that it was not a gallows at all. For affixed to the top cross-bar was a large, bottomless glass basin, inside which was a glass bulb that glowed with a strange green light; and in the heart of the bulb a bright spot of red.
It was all clear enough so far. The peculiar sound that filled the air was the hum of the interrupter; the bulb was, of course, a Crookes tube, and the red spot inside it, the glowing red-hot disc of the anti-cathode. Clearly an X-ray photograph was being made; but of what? I strained my eyes, peering into the gloom at the foot of the gallows, but though I could make out an elongated object lying on the floor directly under the bulb, I could not resolve the dimly seen shape into anything recognizable. Presently, however, Dr. Norbury supplied the clue.
"I am rather surprized," said he, "that you chose so composite an object as a mummy to begin on. I should have thought that a simpler object, such as a coffin or a wooden figure, would have been more instructive."
"In some ways it would," replied Thorndyke, "but the variety of materials that the mummy gives us has its advantages. I hope your father is not ill, Miss Bellingham."
"He is not at all well," said Ruth, "and we agreed that it was better for me to come alone. I knew Herr Lederbogen quite well. He stayed with us for a time when he was in England."
"I trust," said Dr. Norbury, "that I have not troubled you for nothing. Herr Lederbogen speaks of 'our erratic English friend with the long name that I can never remember,' and it seemed to me that he might be referring to your uncle."
"I should hardly have called my uncle erratic," said Ruth.
"No, no. Certainly not," Dr. Norbury agreed hastily. "However, you shall see the letter presently and judge for yourself. We mustn't introduce irrelevant topics while the experiment is in progress, must we, Doctor?"
"You had better wait until we have finished," said Thorndyke, "because
I am going to turn out the light. Switch off the current, Polton."