The blocks of stone below the cornice are 2 feet thick, and those of the solid portion of the tower are cut to form a lock on each other in each course, and the courses are fastened together with wrought iron bolts 2½ inches thick and 2 feet long. The tower is bolted to the foundation rock with bolts 3 feet long which enter the bed rock 21 inches, the other courses receiving the bolts for 9 inches. Each bolt is wedged at both ends, and the bolt holes, which were made with a diamond drill, after the stones were in place, are plugged with pure portland cement, now as hard as the stone itself. Hence the tower is, in effect, a monolith. The stones were cut at the depot at Scammon’s Harbor, 16 miles away, and fitted, course by course, on a platform of masonry. The stones were so well prepared that a course could be set, drilled, and bolted in 3 days. The foundation, 11 feet under water, was laid in a cofferdam protected by a crib work of 12-inch timber, built upon ways at the depot, as a ship might have been, than launched and towed by a number of steamers to the reef and grounded on the site. This crib was 92 feet square and 24 feet high. This afforded a protected pond for the cofferdam, a landing wharf, and quarters for the men all 12 feet above water. The cofferdam was then pumped out until the bedrock was exposed and on this bedrock the masonry courses were laid. [Illustration] A severe gale in September 1872 did considerable damage, though only of a temporary character, exposing the east face of this crib at a point where it had not been sheathed to protect it from the ice during the winter. It swept away the temporary cribs and nearly destroyed the workmen’s quarters. After the winter of 1873-74, when the keepers returned to the newly completed tower, they found the ice piled against it at a height of 30 feet, or 7 feet higher than the doorway, and they could not gain entrance until they had cut away the iceberg of which the lighthouse formed the core. The light now flashes alternately white and red, every 60 seconds, the white light being 400,000 candlepower and the red light 80,000 candlepower, both second-order electric, and visible for 17 miles. There is also a 100 candlepower white winter light which flashes every 5 seconds. An air-diaphone fog signal is also located at the station. (1) (2) _MICHIGAN_ STANNARD ROCK LIGHTHOUSE, LAKE SUPERIOR [Illustration]