f health it would be absurd
for you to attempt it. Apart from which there is a possibly more
important task to be undertaken here, outside."

He turned his eyes upon Sime, who was listening intently, then
continued:

"Whilst we are penetrating to the interior by means of the sloping
passage on the north side, Ali Mohammed and yourself must mount guard
on the south side."

"What for?" said Sime rapidly.

"For the reason," replied Dr. Cairn, "that there is an entrance on to
the first stage--"

"But the first stage is nearly seventy feet above us. Even assuming
that there were an entrance there--which I doubt--escape by that means
would be impossible. No one could climb down the face of the pyramid
from above; no one has ever succeeded in climbing up. For the purpose
of surveying the pyramid a scaffold had to be erected. Its sides are
quite unscaleable."

"That may be," agreed Dr. Cairn; "but, nevertheless, I have my reasons
for placing a guard over the south side. If anything appears upon the
stage above, Rob--_anything_--shoot, and shoot straight!"

He repeated the same instructions to Ali Mohammed, to the evident
surprise of the latter.

"I don't understand at all," muttered Sime, "but as I presume you have
a good reason for what you do, let it be as you propose. Can you give
me any idea respecting what we may hope to find inside this place? I
only entered once, and I am not anxious to repeat the experiment. The
air is unbreathable, the descent to the level passage below is stiff
work, and, apart from the inconvenience of navigating the latter
passage, which as you probably know is only sixteen inches high, the
climb up the vertical shaft into the tomb is not a particularly safe
one. I exclude the possibility of snakes," he added ironically.

"You have also omitted the possibility of Antony Ferrara," said Dr.
Cairn.

"Pardon my scepticism, doctor, but I cannot imagine any man
voluntarily remaining in that awful place."

"Yet I am greatly mistaken if he is not there!"

"Then he is trapped!" said Sime grimly, examining a Browning pistol
which he carried. "Unless--"

He stopped, and an expression, almost of fear, crept over his stoical
features.

"That sixteen-inch passage," he muttered--"with Antony Ferrara at the
further end!"

"Exactly!" said Dr. Cairn. "But I consider it my duty to the world to
proceed. I warn you that you are about to face the greatest peril,
probably, which you will ever be call