The contracts were signed in September, 1882, and the task was commenced. The first disaster was a blessing in disguise, for the new engineers were able to turn the mistakes of their predecessors to advantage. They designed a caisson of oval shape, with pointed ends, measuring 46 feet in length by 36 feet wide. It was an elaborate, staunch structure, towering to a height of 60¾ feet when launched. At a height of 8 feet from the bottom edge was a massive flooring built of iron. The space below constituted the area in which the men were to work upon the sea-bed, excavating the sand under compressed air, while the lower rim was a cutting edge, so as to facilitate the sinking of the mass as the sand was removed. The upper part of the caisson was divided into four floors, each of which was set aside for a specific purpose. The lowest was the concrete-mixing chamber; that above carried the machinery and boilers; the third floor formed the living-quarters for the men who worked and slept on the structure; while the top floor formed a deck, and carried two powerful cranes whereby the material was lifted from the boats which drew alongside. Of course, when the caisson had been lowered into the water and was eating its way deeper and deeper into the sand, these platforms had to be moved higher and higher from time to time, as the base of the tun became filled with concrete, the outer walls of the fabric being increased to keep the top well above high-water mark. When the caisson was completed on shore and sent into the water, it was an impressive-looking monster. The shell itself weighed 245½ tons, and with the various accessories aboard the weight was brought up to some 335 tons. It then had to be loaded down to the required depth for towing, for which purpose ballast in the form of pig-iron, concrete, and bricks, to the extent of another 245 tons, was stowed aboard, while delicate precautions were taken to maintain stability. The combined efforts of 120 men, working day and night for 127 days, were required to erect this caisson, and on April 1, 1883, it was ready for its transportation to the site.