Work was resumed in February, 1884, and continued more or less regularly until November. Interruptions were of frequent occurrence, so that only about one-quarter of the time available could be turned to useful account. The structure which had been towed out of Bremerhaven a year previously had disappeared from sight, the rim of the barrel built on dry land being about 4 feet below water; but, of course, as the work proceeded and the caisson sank, its walls were extended upwards, as already explained. When the structure had been sunk to its designed depth, the steel shell was 107½ feet in height, from the cutting edge to the top projecting above the water, and nearly 40 feet of its height was buried in the Rothersand. To sink it to this level required the removal of 3,000 cubic yards of sand from beneath the bottom floor of the structure; while 49,100 tons of material were brought out from Bremerhaven and built into the steel shell to render it a solid elliptical mass, with the exception of a short central hollow space which has a narrow conduit connection with the outer sea, and which, fitted with a float, acts as a tide-gauge which may be read in the lighthouse. From this massive concrete pedestal rises the tower proper, which at the base is circular, with a diameter of 33¾ feet. This base rises in the form of a graceful concave curve to a height of 26 feet, and is solid except for two water-tanks. At the entrance level the tower is 23 feet in diameter. Above this are disposed four floors, comprising the cellar, storeroom, kitchen, and living-quarters for the men, crowned by the lantern, the gallery of which is 80½ feet above low-water. The external appearance of this interesting lighthouse is somewhat different from the general conception of such a building. Instead of being merely a circular top and lantern, there are three semicircular turret-like projections on the dwelling-room and lantern levels, which serve for directing and warning lights as well as for a lookout station.