“_Sumburgh Head_ Lighthouse is situate on the southern promontory of the Mainland of the Shetland Islands, in north latitude 59° 52´, and longitude 1° 15´ west of London. The Lighthouse, by compass, bears from Hangcliff-head in Noss Island SW. by W. ¼ West, distant 21 miles. From Fair Island NE. by E. ½ East, 26 miles. And from the Island of Foula, SE. by S. ¼ South, distant 28 miles. In reference to these bearings, the light is visible to the mariner from the southward, between Noss and Foula Islands. This light is known to mariners as a “Stationary light from oil with reflectors;” and being elevated 300 feet above the medium level of the sea, it is seen, like a star of the first magnitude, at the distance of seven or eight leagues, and at intermediate distances, according to the state of the atmosphere.” [Sidenote: Built with double walls.] From the very exposed situation of the promontory of Sumburgh Head, and the great difficulty experienced in preserving the walls of light-houses in a water-tight state, the writer followed a new plan with the buildings at this station, in having made the whole of the external walls double; the masonry of the outward wall being lined with brick instead of lath-work, with a space of three inches left between the double walls. This method was of course, more expensive in the first instance, but will ultimately be much more economical, as repairs, in these remote situations, are unavoidably very expensive. This house is free of dampness, and has not admitted a single drop of water through any part of the walls during the storms of two successive winters, although the force of the wind is such, that the light-keepers, when out of doors, are frequently obliged to move upon their hands and knees, to prevent their being blown off the high land. In such states of the weather, accompanied by rain, it is hardly possible to prevent a single wall from admitting water. _Carr Rock._ The Carr forms the seaward termination of a reef of sunken rocks which appear at low-water, extending about a mile and three quarters from the shore of Fifeness, on the northern side of the entrance of the Firth of Forth. The very dangerous position of this rock, as a _turning point_, in the navigation of the northern-bound shipping of the Firth , will be seen from the chart of the coast, Plate IV. It seemed necessary, therefore, for the safety of navigation, that the Carr Rock, in connection with the several light-houses of the Bell Rock, Isle of May, and Inchkeith, should be made as easily distinguishable to the mariner as possible. [Sidenote: Shipwrecks at the Carr Rock.]