The men on the caisson, however, experienced one of the most sensational nights in their lives. As the tide rose, they found their novel home to be behaving somewhat curiously. It moved, and then heeled over. This was an alarming state of affairs, especially as the list gradually became worse and worse. They shouted frantically for help, but, a heavy fog having descended upon the shoal, their cries were absorbed by the white pall. At last the caisson careened over to such a degree that the men could not keep their feet, while the depressed edge was in danger of being submerged. The men crawled to the opposite or elevated side, and held on for their lives, expecting every moment that the structure would give a heave and roll over. It was a terribly anxious time for them, and at last, when the constructional steamer came alongside in the morning, they scuttled down the ropes from their perilous perch to the deck below, thankful for having escaped, as they thought, a certain watery grave. The engineers spared no effort to save their work. They were harassed at every tide because the water rose above the depressed edge and flooded the interior. With all speed the wall at this point was increased in height, so as to prevent inundation. Then, stormy weather having cut away the sand under the elevated side, the structure gradually righted itself. When it had regained its vertical position, it was found that no serious damage had been done, but rather that the engineers had profited, inasmuch as the caisson had buried itself some 16 feet into the sand.