Tamre watched their faces eagerly, turning his head to each speaker in
turn, uncomprehending, but aping Royan's expression like a mirror. If
she nodded he nodded, when she frowned he did the same, and when she
smiled he giggled happily.
'It's a big river.' Royan shook her head, while Tamre wagged his from
side to side in sympathy and looked wise.
'What method would he have used? An earthen dam?
Surely not?' i 'The Egyptians used earthen canals and dams for a great
many of their irrigation works,'Nicholas mused. 'On the other hand, when
they had rock available to work with ..', they used it extensively. They
were expert masons. You have stood in the quarries at Aswan.'
'Not much topsoil here in the gorge,' she pointed out.
'But on the other hand, there is plenty of rock. It's like a geological
museum. Every type of rock that you could wish for.'
'I agree,' he said. 'Rather than an earthen wall, Taita would most
probably have used a masonry and rock fill.
That is the type of dam the ancients built in Egypt, long before his
time. If that is the case, there is a chance that traces of it have
survived.'
'Okay. Let's work on that hypothesis. Taita built a dam of rock stabs,
and then he breached it again. Where would we find the remains of it?'
'We would have to start searching on the actual site,' he answered.
'There at the neck of the gorge. Then we would have to search downstream
from there.'
They scrambled down the slope again, with Tamre picking out the easiest
route for Royan, stopping to beckon her whenever she faltered or paused
for breath. They came out in the neck of the valley and stood on the
rocky bank of the river, looking about them.
'How high would the wall have been?' Royan asked.
'Not too high. Again, I can't give you a precise answer until I have
shot the levels.' He climbed a little way up the side of the wall. There
he squatted and turned his head back and forth, looking first down the
length of the valley and then towards the lip of the waterfall that
dropped into the mouth of the chasm.
Three times he changed his position, on each occasion moving a few paces
higher up the slope. The cliff became steeper the higher he climbed. In
the end he was clinging precariously to the side of it, but he seemed
satisfied. Then he called down to her.
'I would say this is about it, where I am now. This would be the height
of the dam wall. It looks about fifteen feet high to me.'
Royan was still standing on the bank, and now she turned and stared
across at the far bank of the river, estimating the distance to the
limestone cliff rising above it.
'Roughly a hundred feet across,' she shouted up to him.
'About that,' he agreed. 'A lot of work, but not impossible.'
'Taita. was never one to be daunted by size or difficulty.' She cupped
her hands around her mouth to shout up to him. 'While you are up there,
can you see any sign of works? Taita would have had to pin the dam wall
into the cliff.'
He scrambled along the cliff, keeping to the same level, until he was
