Under such abnormal conditions of working the masons had many exciting moments. No matter how smooth was the sea, several renegade waves would plunge over the ledge. The masons had to be prepared for these unwelcome visitors, and precautions had to be introduced to prevent them being washed off their slender foothold. A substantial iron staging was erected over the working area on the rock, to facilitate the handling of the building material. A number of ropes were attached to this staging, the free ends of which dangled beside the workmen. These were the life-lines, one being provided for each man. A lookout was posted, who, when he saw a wave approaching and bent upon sweeping the rock, gave a shrill signal. Instantly each workman dropped his tools, clutched his life-line tightly, threw himself prostrate on the rock, and allowed the wave to pass over him. The situation certainly was uncomfortable, and the men often toiled in soddened clothes, but an involuntary bath was preferable to the loss of a life or to broken limbs. Work advanced so slowly that during the first two years, which were devoted to the excavation of the pit and the preparations of the rock-face, only 287 hours’ work were accomplished. In the third year this task was completed, and four stones laid in a further 130 hours 21 minutes. By the end of the working season of 1859 twenty-six courses were finished, so that, while the volume of work fulfilled in 1,102 hours 21 minutes, and spread over five years, certainly was not imposing, it was remarkable under the circumstances. The stones for the foundations were sent from shore with the indication -3’ 5”, -2’ 9”, -1’ 3”, and so on, indicating that these stones were prepared for positions 3 feet 5 inches, 2 feet 9 inches, and so on, below zero. And the zero mark was 21 inches below water! Above the zero mark the stones were prefixed by a “plus” sign. The shaft is purely conical, and solid except for a central well extending from the foundations up to the level of the entrance. The successive courses of stones were secured to one another, and each stone was attached to its neighbour in the ring by the aid of heavy iron dogs, so that the lower part of the shaft forms a practically solid homogenous mass. What are known as continuous “dowels” were sunk through each course of masonry into the holes in the solid rock prepared by Captain Swift for his skeleton light, this further attachment of the mass to the ledge being continued until the twelfth course was gained. Thus additional security is obtained by anchoring the tower firmly to the reef.