its ponderous progress until it reached the confluence of the two Niles. The other Nile came down from the east. It was fresh and sweet as the mountain stream that was its source. At this season of High Nile its waters were tinted a pale blue grey by the silt it had scoured from the mountainous ranges of Abyssinia. It was named for this colour. The Blue Nile was slightly narrower than its twin, but was still a massive serpent of water. The rivers came together at the apex of the triangle of land on which the City of the Elephant's Trunk stood. That was the meaning of its name, Khartoum. The two Niles did not mingle at once. As far downstream as Rebecca could see they ran side by side in the same bed, each maintaining its own distinct colour and character until they dashed together on to the rocks at the entrance to the Shabluka Gorge twenty miles on and were churned into a tumultuous union. 'You are not listening to me, my darling,' said her father sharply. Rebecca smiled as she turned to face him. 'Forgive me, Father, I was distracted.' 'I know. I know. These are trying times,' he agreed. 'But you must face up to them. You are no longer a child, Becky.' 'Indeed I am not,' she agreed vehemently. She had not intended to whine -- she never whined. 'I was seventeen last week. Mother married you when she was the same age.' 'And