The Wolf tower follows the generally accepted lines, and is solid at the base. It is wrought throughout of granite, the stones being joggled together. One ingenious measure was adopted in connection with the lower courses in order to prevent the action of the waves from breaking up the cement in the exposed joints and setting up disintegration. The upper surface of each stone is given a wide rabbet, and the stone above fits into the recess so that the horizontal joint between the two is covered by the outer fillet, thereby protecting it completely. This practice was followed throughout all the lower courses to a height of 39 feet, and the security thus obtained is reflected by the strength of the tower to-day after half a century’s wear. Work proceeded so slowly in the early stages, owing to the abnormal conditions, that by the end of 1864 only thirty-seven stones in the second course of masonry were laid. In the meantime, however, the landing-stage had been practically completed, and the erection of the crane enabled the blocks for the tower to be transferred to the rock with greater ease and rapidity. The tower, 135 feet in height, was completed on July 19, 1869, while the light was brought into service early in the following year. Eight years were expended upon the enterprise, and during this period 296 landings were effected upon the rock and 1,814 hours of labour were consummated. This is equal to about 101 working days of ten hours each, or, on the average, less than one hour every day of the years occupied in the undertaking. The lantern throws a powerful white light, which in clear weather may be seen from twenty to twenty-five miles away. The cost of the enterprise was £62,726, or $313,630--nearly twice that of the first Bishop Rock light. [Illustration: _By courtesy of Messrs. D. and C. Stevenson._ THE CHICKEN ROCK LIGHTHOUSE, OFF THE ISLE OF MAN. It marks a dangerous reef. The revolving light of 143,000 candle-power is visible for sixteen miles. Although the lantern is 143 feet above the water, the waves frequently engulf it.] Another gaunt structure rears itself from a reef a few miles to the north-west of the Wolf, and a short distance off the Land’s End. This is the Longships light. The name itself suggests a light-vessel, and a stranger is surprised to learn that it is an imposing building, worthy of comparison with the two other structures already described which guard the Scillies. Although it is within a short distance of the mainland, its exposed situation rendered its construction as exasperatingly difficult as that of both the Bishop and Wolf lights. A few miles farther north another powerful light indicates the “Kingdom of Heaven,” as the black hump of Lundy Island, rising out of the Bristol Channel, is colloquially called, from the name of its clerical owner.