After the first assault they resorted to tactics more likely to succeed. They attacked twice by night. But, fortunately for the defence, the nights were fine and starry, a full moon was up, and it was possible to see the enemy long before he reached the walls of the fort.
For all that, the greatest vigilance was necessary both by day and night, to avoid being taken by surprise. One or other of the defenders was always on guard. Even Peter Klein was of some use. Though he could not be relied upon to act with courage or promptitude, his eyesight was good enough, and he took his turn at sentry by day. Moreover, he was in such abject terror of falling into the hands of his own people that Harry suspected that the German authorities at Dualla had learnt something of the Sunstone and von Hardenberg's private mission to the Cameroons.
By night, when the fort might be rushed, they thought it best not to leave their destiny in the hands of one who had failed them so constantly. The only occasion on which Klein had covered himself with credit was at a moment when fear had so possessed him that he lost all sense of danger and became for the time being a raving madman.
It would be wearisome to describe the details of the siege as it continued day by day. There is no question that the defenders would have held their own for many weeks had it not been that gradually a calamity was drawing down upon them. They were running short of ammunition. Their bandoliers were nearly empty.
The Germans kept up a constant fire upon the fort, and the garrison, in self-defence, was obliged to answer back. They calculated that, with the greatest economy, they had cartridges sufficient to last them only four days more. It was then that Klein, Harry, and the guide entered the hut and held consultation together. Jim Braid was on sentry, stationed on the parapet. The sun was setting in the west.
It was Fernando who was the first to speak.
"The situation is very plain," said he. "We can hold out until our ammunition is exhausted, and then retire by way of the tunnel, still hoping to reach the caves in advance of von Hardenberg, or we may retire to-night.
"Which do you advise?" asked Harry.
"I suggest," said the guide, "that we go at once. We shall need ammunition on our return journey to the coast. We have many miles to traverse. Every moment we delay means a further expenditure of ammunition. We have not a cartridge to spare."
"Then," said Harry, "it is settled: we leave the fort this evening."