The plan of this excursion was proposed by Pencroft, and Cyrus Harding fully acquiesced in it, for he himself wished to see this part of his domain.

The weather was variable, but the barometer did not fluctuate by sudden movements, and they could therefore count on tolerable weather. However, during the first week of April, after a sudden barometrical fall, a renewed rise was marked by a heavy gale of wind, lasting five or six days; then the needle of the instrument remained stationary at a height of twenty-nine inches and nine-tenths, and the weather appeared propitious for an excursion.

The departure was fixed for the 16th of April, and the "Bonadventure," anchored in Port Balloon, was provisioned for a voyage which might be of some duration.

Cyrus Harding informed Ayrton of the projected expedition, and proposed that he should take part in it, but Ayrton preferring to remain on shore, it was decided that he should come to Granite House during the absence of his companions. Master Jup was ordered to keep him company, and made no remonstrance.

On the morning of the 16th of April all the colonists, including Top, embarked. A fine breeze blew from the south-west, and the "Bonadventure" tacked on leaving Port Balloon so as to reach Reptile End. Of the ninety miles which the perimeter of the island measured, twenty included the south coast between the port and the promontory. The wind being right ahead it was necessary to hug the shore.

It took the whole day to reach the promontory, for the vessel on leaving port had only two hours of ebb tide and had therefore to make way for six hours against the flood. It was nightfall before the promontory was doubled.

The sailor then proposed to the engineer that they should continue sailing slowly with two reefs in the sail. But Harding preferred to anchor a few cable-lengths from the shore, so as to survey that part of the coast during the day. It was agreed also that as they were anxious for a minute exploration of the coast they should not sail during the night, but would always, when the weather permitted it, be at anchor near the shore.

The night was passed under the promontory, and the wind having fallen, nothing disturbed the silence. The passengers, with the exception of the sailor, scarcely slept as well on board the "Bonadventure" as they would have done in their rooms at Granite House, but they did sleep however. Pencroft set sail at break of day, and by going on the larboard tack they could keep close to the shore.

The colonists knew this beautiful wooded coast, since they had already explored it on foot, and yet it again excited their admiration. They coasted along as close in as possible, so as to notice everything, avoiding always the trunks of trees which floated here and there. Several times also they anchored, and Gideon Spilett took photographs of the superb scenery.

About noon the "Bonadventure" arrived at the mouth of Falls River. Beyond, on the left bank, a few scattered trees appeared, and three miles further even these dwindled into solitary groups among the western spurs of the mountain, whose arid ridge sloped down to the shore.

What a contrast between the northern and southern part of the coast! In proportion as one was woody and fertile so was the other rugged and barren! It might have been designated as one of those iron coasts, as they are called in some countries, and its wild confusion appeared to indicate that a sudden crystallization had been produced in the yet liquid basalt of some distant geological sea. These stupendous masses would have terrified the settlers if they had been cast at first on this part of the island! They had not been able to perceive the sinister aspect of this shore from the summit of Mount Franklin, for they overlooked it from too great a height, but viewed from the sea it presented a wild appearance which could not perhaps be equaled in any corner of the globe.

The "Bonadventure" sailed along this coast for the distance of half a mile. It was easy to see that it was composed of blocks of all sizes, from twenty to three hundred feet in height, and of all shapes, round like towers, prismatic like steeples, pyramidal like obelisks, conical like factory chimneys.