On the 20th of November the bridge was finished.  The movable part, balanced by the counterpoise, swung easily, and only a slight effort was needed to rise it; between its hinge and the last cross-bar on which it rested when closed, there existed a space of twenty feet, which was sufficiently wide to prevent any animals from crossing.

The settlers now began to talk of fetching the balloon-case, which they were anxious to place in perfect security; but to bring it, it would be necessary to take a cart to Port Balloon, and consequently, necessary to beat a road through the dense forests of the Far West.  This would take some time.  Also, Neb and Pencroft having gone to examine into the state of things at Port Balloon, and reported that the stock of cloth would suffer no damage in the grotto where it was stored, it was decided that the work at Prospect Heights should not be discontinued.

“That,” observed Pencroft, “will enable us to establish our poultry-yard under better conditions, since we need have no fear of visits from foxes nor the attacks of other beasts.”

“Then,” added Neb, “we can clear the plateau, and transplant wild plants to it.”

“And prepare our second corn-field!” cried the sailor with a triumphant air.

In fact, the first corn-field sown with a single grain had prospered admirably, thanks to Pencroft’s care.  It had produced the ten ears foretold by the engineer, and each ear containing eighty grains, the colony found itself in possession of eight hundred grains, in six months, which promised a double harvest each year.

These eight hundred grains, except fifty, which were prudently reserved, were to be sown in a new field, but with no less care than was bestowed on the single grain.

The field was prepared, then surrounded with a strong palisade, high and pointed, which quadrupeds would have found difficulty in leaping.  As to birds, some scarecrows, due to Pencroft’s ingenious brain, were enough to frighten them.  The seven hundred and fifty grains deposited in very regular furrows were then left for nature to do the rest.

On the 21st of November, Cyrus Harding began to plan the canal which was to close the plateau on the west, from the south angle of Lake Grant to the angle of the Mercy.  There was there two or three feet of vegetable earth, and below that granite.  It was therefore necessary to manufacture some more nitro-glycerine, and the nitro-glycerine did its accustomed work.  In less than a fortnight a ditch, twelve feet wide and six deep, was dug out in the hard ground of the plateau.  A new trench was made by the same means in the rocky border of the lake, forming a small stream, to which they gave the name of Creek Glycerine, and which was thus an affluent of the Mercy.  As the engineer had predicted, the level of the lake was lowered, though very slightly.  To complete the enclosure the bed of the stream on the beach was considerably enlarged, and the sand supported by means of stakes.