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 surprised,” 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.”
The green light vanished from the bulb, the hum of the interrupter swept down an octave or two and died away. Then Thorndyke and Dr. Norbury rose from their chairs and went toward the mummy, which they lifted tenderly while Polton drew from beneath it what presently turned out to be a huge black paper envelope. The single glow-lamp was switched off, leaving the room in total darkness until there burst out suddenly a bright orange red light immediately above one of the trays.
We all gathered round to watch, as Polton—the high priest of these mysteries—drew from the black envelope a colossal sheet of bromide paper, laid it carefully in the tray and proceeded to wet it with a large brush which he had dipped in a pail of water.
“I thought you always used plates for this kind of work,” said Dr. Norbury.
“We do, by preference; but a six-foot plate would be impossible, so I had a special paper made to the size.”
There is something singularly fascinating in the appearance of a developing photograph; in the gradual, mysterious emergence of the picture from the blank, white surface of plate or paper. But a skiagraph, or X-ray photograph, has a fascination all its own. Unlike the ordinary photograph, which yields a picture of things already seen, it gives a presentment of objects hitherto invisible; and hence, when Polton poured the developer on the already wet paper, we all craned over the tray with the keenest curiosity.
The developer was evidently a very slow one. For fully half a minute no change could be seen in the uniform surface. Then, gradually, almost insensibly, the marginal portion began to darken, leaving the outline of the mummy in pale relief. The change, once started, proceeded apace. Darker and darker grew the margin of the paper until from slaty gray it had turned to black; and still the shape of the mummy, now in strong relief, remained an enlongated patch of bald white. But not for long. Presently the white shape began to be tinged with gray, and, as the color deepened, there grew out of it a paler form that seemed to steal out of the enshrouding gray like an apparition, spectral, awesome, mysterious. The skeleton was coming into view.
“It is rather uncanny,” said Dr. Norbury. “I feel as if I were assisting at some unholy rite. Just look at it now!”
The gray shadow of the cartonnage, the wrappings and the flesh was fading away into the background and the white skeleton stood out in sharp contrast. And it certainly was rather a weird spectacle.
“You’ll lose the bones if you develop much farther,” said Dr. Norbury.
“I must let the bones darken,” Thorndyke replied, “in case there are any metallic objects. I have three more papers in the envelope.”
The white shape of the skeleton now began to gray over and, as Dr. Norbury had said, its distinctness became less and yet less. Thorndyke leaned over the tray with his eyes fixed on a point in the middle of the breast and we all watched him in silence. Suddenly he rose. “Now, Polton,” he said sharply; “get the hypo on as quickly as you can.”
Polton, who had been waiting with his hand on the stopcock of
