a brief but electric silence. Dr.
Cairn's face was very stern and Sime, with his hands locked behind
him, stood staring out of the window into the palmy garden of the
hotel. Robert Cairn looked from one to the other excitedly.

"What did he say, sir?" he cried, addressing his father. "It had
something to do with--"

Dr. Cairn turned. Sime did not move.

"It had something to do with the matter which has brought me to
Cairo," replied the former--"yes."

"You see," said Robert, "my knowledge of Arabic is _nil_--"

Sime turned in his heavy fashion, and directed a dull gaze upon the
last speaker.

"Ali Mohammed," he explained slowly, "who has just left, had come down
from the Fayum to report a singular matter. He was unaware of its real
importance, but it was sufficiently unusual to disturb him, and Ali
Mohammed es-Suefi is not easily disturbed."

Dr. Cairn dropped into an armchair, nodding towards Sime.

"Tell him all that we have heard," he said. "We stand together in this
affair."

"Well," continued Sime, in his deliberate fashion, "when we struck our
camp beside the Pyramid of Meydum, Ali Mohammed remained behind with a
gang of workmen to finish off some comparatively unimportant work. He
is an unemotional person. Fear is alien to his composition; it has no
meaning for him. But last night something occurred at the camp--or
what remained of the camp--which seems to have shaken even Ali
Mohammed's iron nerve."

Robert Cairn nodded, watching the speaker intently.

"The entrance to the Meydum Pyramid--," continued Sime.

"_One_ of the entrances," interrupted Dr. Cairn, smiling slightly.

"There is only one entrance," said Sime dogmatically.

Dr. Cairn waved his hand.

"Go ahead," he said. "We can discuss these archaeological details
later."

Sime stared dully, but, without further comment, resumed:

"The camp was situated on the slope immediately below the only _known_
entrance to the Meydum Pyramid; one might say that it lay in the
shadow of the building. There are tumuli in the neighbourhood--part of
a prehistoric cemetery--and it was work in connection with this which
had detained Ali Mohammed in that part of the Fayum. Last night about
ten o'clock he was awakened by an unusual sound, or series of sounds,
he reports. He came out of the tent into the moonlight, and looked up
at the pyramid. The entrance was a good way above his head, of course,
and quite fifty or sixty yards from the point where he w