of crudely dressed stone, This whole length of the tunnel had also been
submerged, for it lay below the natural level of the river before it had
been dammed. The paving under their feet was wet and covered with a
slime that had not yet had time to dry out since it had been exposed by
the receding waters. The roof and walls of the tunnel ran with moisture,
and the air was dank and cold and smelled of mud and rot.
They waited for Sapper to string the cables for the lights across the
causeway. He set up the lamps and switched them on. At once they were
aware that ahead of them the shaft had begun to rise at an angle of
about twenty degrees.
'You can see what the old devil Taita. was up to here.
He has taken us down well below water level to flood the tunnel to a
length and depth that nobody would be able to swim along. Now he is
angling up again,' Nicholas pointed out to Royan. They started forward,
moving slowly up the ascending shaft, and Nicholas counted aloud each
pace he took.
'One hundred and eight, one hundred and nine, one hundred and ten-'
suddenly they came to the recent low river level. It was clearly marked
as a dry line on the walls of the tunnel. The paving under their feet
was also dry and free of the slippery coating of slime. Fifty paces
further on they passed the high flood level of the river, which was just
as clearly etched on the rock floor and the walls. Beyond that the
tunnel had never been immersed, and the walls were in the same condition
as the Egyptian slave workmen had left them four thousand years earlier.
The marks of the bronze chisels were as pristine as if they had been
inflicted just days before.
Only ten feet beyond the highest point that the river waters had ever
reached, they came out upon a stone landing. Here the floor levelled
out, and then the tunnel turned sharply back upon itself.
'Let's spare a minute just to think about this as a feat of
engineering.' Nicholas took Royan's arm and pointed back down the
tunnel. 'Taita has placed this landing on which we are standing
precisely above the high-water mark of the river. How did he work it out
so exactly? He had no dumpy level, and only the crudest measuring
equipment.
is. It's a he And yet he calculated it as accurately as a piece of
work.'
'Well, he tells us repeatedly in the scrolls that he is a genius. I
suppose we will have to believe him now.' She pulled against his grip.
'Let's go on. I must see what lies around this corner,' she urged.
Side by side they turned through the one hundred and eighty degree
corner and Nicholas held the hand lamp high, with the electrical cable
trailing back down the shaft behind him. As he lit the way ahead, Royan
exclaimed aloud and seized Nicholas's free hand. Both of them froze with
astonishment.
Taita had designed the turning of the ascending ramp for dramatic
effect. The lower section of the shaft through which they had passed was
'crudely constructed, the walls irregular and undressed, the roof lumpy
and cracked. Taita had calculated his levels so finely that he had known
