Upon reaching Nassau, the party immediately set to work to build a suitable barge. The construction of the barge, which was forty feet in length and sixteen feet in width, occupied a month. Amid ships it contained a well measuring six feet by ten feet, through which the deep-sea tube was to be lowered into the sea. The well was boarded round with heavy, water-tight planks.
When the craft was finished, the party christened it "Jules Verne”, in honour of the esteemed French imaginative writer, whose book, “Twenty Thousand Leagues Under the Sea", has charmed thousands of adventurous schoolboys, and has delighted many a stolid adult reader who loves to read a romance that is based on scientific facts. To tow the “Jules Verne" the Williamson brothers secured a big gasoline power boat from a native, who also happened, curiously enough, to be an ardent admirer of the charming French writer, and had named his boat the “Nautilus”. So, here was the enterprise now fairly started on its way in the real adventurous spirit of “Twenty Thousand Leagues Under the Sea".
The Williamsons had brought with them two immense glass discs, made in France, each one five feet in diameter and one and a half inches thick, for the observation window. They had also provided themselves with a battery of nine Cooper Hewitt lights, arranged in a gridiron, each light having two thousand four hundred candle power, these to be lowered for extra submarine illumination, should that be necessary. These artificial lights, however, were seldom used, owing to the wonderful clearness of the West Indian seas even at considerable depths.
The Williamson submarine deep sea tube, it will be remembered, was described as possessing the dual advantages of strength and flexibility. These were obtained by the use of hundreds of overlapping steel scales or plates, hinged together between annular rings of malleable iron about a foot apart, that form the skeleton of the tube. Over this metallic structure was securely fastened a waterproof fabric of canvas and rubber, the result being a permanently open air shaft down into the sea, a vertical passage-way into which a man may step from the deck of a steamer, and down which he may climb, exactly as one climbs down a ladder, to a depth of hundreds of feet below the surface.
There is no discomfort from breathing compressed air, since there is no necessity to use compressed air. The top of the tube remains open at the deck level like the top of a well, the sides and the bottom being strong enough to resist the pressure of the water of the ocean.