ill afford. We are going to have to build some sort of bridge across
it."
"What kind of bridge?"
"Get Sapper down here. This is his department."
Sapper stood at the brink of the sink-hole and glared across at the far
bank.
Pontoons," he grunted. "How many of those inflatable rafts have you got
squirrelled away?"
"Forget it, Sapper!" Nicholas shook his head. "You are not getting those
dirty great paws of yours on my rafts."
"Suit yourself' Sapper spread his hands in resignation.
"It would be the easiest and quickest way of doing it.
Anchor a raft in the middle and build a catwalk over the top of it. I
need something that floats high-'
"Baobab." Nicholas snapped his fingers. "That should do the trick very
nicely. When it's dried out, baobab wood is as light as balsa. Floats
just as well as one of my inflatable rafts."
"Plenty of baobabs growing along the hills," Sapper agreed. "Every
second tree in this valley seems to be a ruddy baobab."
hree hundred yards from the top of the cliff grew a massive specimen of
Adansonia digitata.
Its smooth bark resembled the skin of one of the great reptiles from the
age of the dinosaurs. Its girth was tremendous - twenty men with
outstretched arms could not have encircled it. The upper branches were
bare and twisted, and it looked as though it had been dead for a hundred
years. Only the heavy velvet-covered pods proved that it still lived;
they hung thickly from the high branches, bursting open to spill the
black seeds which were coated thickly with white cream of tartar.
"The Zulus say that the Nkulu Kulu, the Great Spirit, planted the baobab
upside down with its roots in the air to punish it," Nicholas told Royan
as they looked up at the enormous spread of its branches.
"Why would he want to do that?" she wanted to know.
"What did the poor old baobab do that was so bad?"
"It boasted that it was the.tallest and thickest tree of the forest, and
so the Nkulu Kulu decided to teach it a little lesson in humility."
One of the gigantic branches had snapped off under its own weight, and
lay on the rocky ground beneath the trunk. The wood was white and
fibrous, light as cork.
Under Nicholas's direction the axemen cut it into manageable lengths.
Once they had been carried down the adit shaft to the sink-hole, Sapper
stapled the logs together and floated them across the pool to form a
causeway. He anchored this to the rock face at either end, and then over
it he laid a catwalk of bamboo poles. The bridge of baobab logs floated
high, and although it bobbed and swayed, it could easily support the
weight of a dozen men at a time.
Nicholas was the first one across the sink-hole. He placed a roughly
made ladder against the high vertical bank, and scrambled up into the
mouth of the adit on the far side of the pool. Royan was close behind
him.
The two of them stood in the entrance to this continuation of the shaft,
and as soon as Nicholas shone his torch into it they realized that the
nature of the construction had changed. This section had not been so
heavily scoured out and eroded by the rush of river water through it.
The main flow must have drained away through the sink-hole. The
dimensions were the same, three metres wide by two high, but the
rectangular shape was more precise and although the walls and roof were
rough, like IL
those of a mine, the marks of the tools that had shaped it were now
clearly visible. The footing of the tunnel was roughly paved with slabs
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
that the lower levels of the shaft would be submerged and damaged by the
water. He had wasted no effort on beautifying them.
Now before them rose a wide stairway. The angle of its ascent was such
that, from where they stood on the landing, the top of it was hidden
from their view. Each step stretched the full width of the tunnel, and
rose, a hand's breadth. The treads were cut from slabs of mottled
gneiss, polished and fitted to each other so precisely that the joints
between them were barely visible. The roof of the tunnel was three times