There was a low cliff of red sandstone, from a grotto at whose foot the
stream gushed. The entrance was screened by a heavy growth of ferns, and
Nicholas went down on his knees to pull them aside and peer into the low
opening.
"What can you see?" Royan demanded behind him.
"Not much. It's dark in there, but it seems to go in for quite some
way."
"You are too big to get in there. You had better let me go in."
"Good place for water cobra," he remarked. "Lots of frogs for them to
eat. Are you sure you want to go?"
"I never said that I wanted to." She sat on the bank while she unlaced
her shoes, then lowered herself into the stream. It came halfway up her
thighs, and she waded forward against the flow with difficulty.
She was forced to bend almost double to creep under the overhanging roof
of the grotto. As she moved deeper in, her voice came back to him.
"The roof gets lower."
"Be careful, dear girl. Don't take any chances."
"I do wish you wouldn't call me "dear girl"." Her voice resonated
strangely from the cave entrance.
"Well, you are both those things, a girl and dear. How about if I call
you "young lady?
"Not that either. My name is Royan."There was silence for a while, then
she called again. "This is as far as I can go. It all narrows down into
a shaft of some sort."
"A shaft?" he demanded.
"Well, at least a roughly rectangular opening."
"Do you think it is the work of humans?"
"Impossible to tell. The water is coming out of it like the spout of a
bath tap. A solid jet."
"No evidence of any excavation? No marks of tools on the rock?"
"Nothing. It's slick and water-worn, covered with moss and algae."
"Could a man get into the opening, I mean if it were not for the water
pressure?"
"If he was a pygmy or a dwarf."
"Or a childT he suggested.
"Or a child," she agreed. "But who would send a child in there?"
"The ancients often used child-slaves. Taita might have done the same."
"Don't suggest it. You are destroying my high opinion of Taita," she
told him as she backed out of the entrance of the grotto. There were
pieces of fern and moss in her hair, and she was soaked from the waist
downwards. He gave her a hand and boosted her back on to the bank. The
curve of her bottom was clearly visible through her wet trousers. He
forced himself not to dwell upon the view.
"So we have to conclude that the shaft is a natural flaw in the
limestone, and not a man-made tunnel?"
"I didn't say that. No. I said that I couldn't be sure.
You might be correct. Children might have been used to dig it. After
all, they were used in the coalmines during the industrial revolution."
"But there is no way that we would be able to explore the tunnel from
this end?"
"Impossible." She was vehement. "The water is pouring out under enormous
pressure. I tried to push my arrn up the shaft, but I did not have the
strength."
"Pity! I was hoping for some more irrefutable evidence, or at least
another lead." He sat down beside her on the bank, and ferreted in his
pack. She looked at him quizzically when he brought out a small black
anodized instrument and opened the lid.
"Aneroid barometer," he explained. "Every good navigator should have
one." He studied it for a moment and then made a note of the reading.
"Explain," she invited.
"I want to know if this spring is below the level of the entrance to the
sink-hole in Taita's pool. If it is not, then we can cross it off our
list of possibilities."
He stood up. "If you are ready, we can move on."
"Where to?"
"Why, Taita's pool, of course. We need a reading up there to establish
the difference in altitude between the two points."
nce Tamre knew where they were headed he showed them a shortcuts so it
took them just under two hours from the fountain head to the top of the
cliff face above Taita's pool.
While they rested, Royan remarked, "Tamre seems to spend most of his
days wandering around in the bush. He knows every path and game trail.
He is an excellent guide."
"Better than Boris, at least," Nicholas agreed, as he fished out his
barometer and took another reading.
"You look particularly pleased with yourself." Royan watched his face as
he studied the instrument.
"Every reason to be," he told her. "Allowing one hundred and eighty feet
for the height of the cliff below us, and another fifty feet for the
depth of the pool, the entrance to the sink-hole is still over a hundred
feet higher than your outlet through the fern grotto on the other side
of the ridge."
"Which means?"
"Which means that there is a distinct possibility that the streams are
one and the same. The inflow is here in Taita's pool and the outflow is
from your grotto."
"How on earth did Taita do it?" she puzzled. "How did he get to the
bottom of the pool? You are the engineering marvel. Tell me how you
would do it."
He shrugged, but she persisted. "I mean, there must be some established
way of doing things like that, of working under water. How do they build
the piers of a bridge, or the foundations of a dam, or - or - or how did
Taita himself build the shaft below the level of the Nile to measure the
flow of the river? You remember the description that he gives of his
hydrograph in River God?"
"The accepted technique is to build a coffer dam " Nicholas said
casually, and then broke off and stared at her. "My oath, you really are
a corker. A dam! What if that old ruffian, Taita, dammed the whole
flipping river!"
"Would that have been possible?"
"I am beginning to believe that with Taita anything is possible. He
certainly had unlimited manpower at his disposal, and if he could build
the hydrograph on the Nile at Aswan, then he understood very clearly the
principles of hydrodynamics. After all, the old Egyptians' lives were
completely bound up with the seasonal inundations of the river and the
management of the floods. From what we have gathered about the old man,
it certainly seems Possible."
"How could we prove it?"
"By finding the remains of his dam. It had to be a hell of a work to
hold the Dandera river. There is a good chance that some evidence of it
remains."
"Where would he have built the dam?" she asked excitedly. "Or let me put
it another way, where would you site the dam if you had to do it?,
"There is one natural place for it," he answered promptly. "The spot
where the trail leaves the river and detours down the valley, and the
river falls into the chasm.
They both turned their heads in unison and looked upstream.
"What are we waiting for?" she asked, and sprang to her feet. "Let's go
look-see!
Their excitement was infectious, and Tamre giggled and danced ahead of
them along the trail through the thorns and then up the valley to the
point where it rejoined the river. The sun had lost the worst of its
heat by the time they stood once again above the falls where the
Dandera. river plunged into the mouth of the chasm, and began its last
lap in the race to join the Nile.
"If Taita. had thrown a dam across here - " Nicholas made a sweep of his