The settlers listened and they thought they heard a sort of chuckling laugh, of which they could not guess the origin. But no voice replied to Pencroft, who in vain repeated his vigorous shouts.

There was something indeed in this to astonish the most apathetic of men, and the settlers were not men of that description. In their situation every incident had its importance, and, certainly, during the seven months which they had spent on the island, they had not before met with anything of so surprising a character.

Be that as it may, forgetting their fatigue in the singularity of the event, they remained below Granite House, not knowing what to think, not knowing what to do, questioning each other without any hope of a satisfactory reply, every one starting some supposition each more unlikely than the last. Neb bewailed himself, much disappointed at not being able to get into his kitchen, for the provisions which they had had on their expedition were exhausted, and they had no means of renewing them.

"My friends," at last said Cyrus Harding, "there is only one thing to be done at present; wait for day, and then act according to circumstances. But let us go to the Chimneys. There we shall be under shelter, and if we cannot eat, we can at least sleep."

"But who is it that has played us this cool trick?" again asked Pencroft, unable to make up his mind to retire from the spot.

Whoever it was, the only thing practicable was to do as the engineer proposed, to go to the Chimneys and there wait for day. In the meanwhile Top was ordered to mount guard below the windows of Granite House, and when Top received an order he obeyed it without any questioning. The brave dog therefore remained at the foot of the cliff while his master with his companions sought a refuge among the rocks.

To say that the settlers, notwithstanding their fatigue, slept well on the sandy floor of the Chimneys would not be true. It was not only that they were extremely anxious to find out the cause of what had happened, whether it was the result of an accident which would be discovered at the return of day, or whether on the contrary it was the work of a human being; but they also had very uncomfortable beds. That could not be helped, however, for in some way or other at that moment their dwelling was occupied, and they could not possibly enter it.

Now Granite House was more than their dwelling, it was their warehouse. There were all the stores belonging to the colony, weapons, instruments, tools, ammunition, provisions, etc. To think that all that might be pillaged and that the settlers would have all their work to do over again, fresh weapons and tools to make, was a serious matter. Their uneasiness led one or other of them also to go out every few minutes to see if Top was keeping good watch. Cyrus Harding alone waited with his habitual patience, although his strong mind was exasperated at being confronted with such an inexplicable fact, and he was provoked at himself for allowing a feeling to which he could not give a name, to gain an influence over him. Gideon Spilett shared his feelings in this respect, and the two conversed together in whispers of the inexplicable circumstance which baffled even their intelligence and experience.

"It is a joke," said Pencroft; "it is a trick some one has played us. Well, I don't like such jokes, and the joker had better look out for himself, if he falls into my hands, I can tell him."

As soon as the first gleam of light appeared in the east, the colonists, suitably armed, repaired to the beach under Granite House. The rising sun now shone on the cliff and they could see the windows, the shutters of which were closed, through the curtains of foliage.

All here was in order; but a cry escaped the colonists when they saw that the door, which they had closed on their departure, was now wide open.

Some one had entered Granite House--there could be no more doubt about that.

The upper ladder, which generally hung from the door to the landing, was in its place, but the lower ladder was drawn up and raised to the threshold.