ngle of Lake Grant. Nothing was easier, since if the level of
the lake was raised two or three feet, the opening would be quite
beneath it. Now, to raise this level they had only to establish a dam
at the two openings made by the lake, and by which were fed Creek
Glycerine and Falls River.

The colonists worked with a will, and the two dams, which besides did
not exceed eight feet in width by three in height, were rapidly erected
by means of well-cemented blocks of stone.

This work finished, it would have been impossible to guess that at that
part of the lake, there existed a subterranean passage through which the
overflow of the lake formerly escaped.

Of course the little stream which fed the reservoir of Granite House and
worked the lift had been carefully preserved, and the water could not
fail. The lift once raised, this sure and comfortable retreat would be
safe from any surprise.

This work had been so quickly done, that Pencroft, Gideon Spilett, and
Herbert found time to make an expedition to Port Balloon. The sailor
was very anxious to know if the little creek in which the _Bonadventure_
was moored, had been visited by the convicts.

"These gentlemen," he observed, "landed on the south coast, and if they
followed the shore, it is to be feared that they may have discovered the
little harbour, and in that case, I wouldn't give half-a-dollar for our
_Bonadventure_."

Pencroft's apprehensions were not without foundation, and a visit to
Port Balloon appeared to be very desirable. The sailor and his
companions set off on the 10th of November, after dinner, well-armed.
Pencroft, ostentatiously slipping two bullets into each barrel of his
rifle, shook his head in a way which betokened nothing good to any one
who approached too near to him, whether "man or beast," as he said.
Gideon Spilett and Herbert also took their guns, and about three o'clock
all three left Granite House.

Neb accompanied them to the turn of the Mercy, and after they had
crossed, he raised the bridge. It was agreed that a gun-shot should
announce the colonists' return, and that at the signal Neb should return
and re-establish the communication between the two banks of the river.

The little band advanced directly along the road which led to the
southern coast of the island. This was only a distance of three miles
and a half, but Gideon Spilett and his companions took two hours to
traverse it. They examined all the border of the ro