From the vicinity of Inchkeith to sandstone quarries, the buildings there were executed of aislar masonry. A platform roof covered with lead, and defended by a parapet wall, was adopted for the light-keepers’ house, instead of a slated roof, with garrets of the common construction; a slated roof being not only more liable to be injured by high winds, but when the attic apartments of such houses are occupied, the premises became more exposed to accident from fire. The slated roof, with iron nails, is also subject to decay, owing to the saline particles with which the air is impregnated, and the sprays of the sea, which, even in such situations as Inchkeith, are often blown over the island, though the site of the light-house is about 175 feet in height. Indeed, at all the original light-house stations in the north, the nails were soon rusted, and the slates getting loose, were often blown off in great numbers, so that in the very depth of Winter, the light-keepers have been obliged to make such a requisition as the following: “A slater is much wanted here, to repair the roof of the house, as upwards of 50 slates have been blown away during the late gales.” Instead, also, of a dwelling-house consisting of only two small apartments as formerly, the house at Inchkeith has four rooms, with other conveniencies, laid out for the accommodation of the families of a principal light-keeper and an assistant, who are now appointed to the charge of each of the Northern Light-houses. [Sidenote: Construction of Light rooms improved.] [Sidenote: Rendered Fire-proof.] An entire change also took place at this period upon the construction of the Light-rooms and the reflecting apparatus, as well as in the extension and enlargement of the accommodation for the light-keepers. The early light-rooms were constructed wholly of timber, excepting the window-sash frames, which were made of cast-iron. The outside of the wooden cupola, covered with sheet copper, and the ceiling and floor with fire-proof plates of tinned iron. But it soon appeared that this construction was liable to great objections, particularly to the risk of accidental fire. The timber roof being also unavoidably shut up from the air, and exposed to a degree of heat sufficient to dry it to the state of tinder, its strength and fibrous qualities were soon lost, and the buildings in danger of being destroyed by the storms of winter. At Inchkeith, on the contrary, the roof is framed of iron, and covered with copper, and the floor is laid with flag-stones; while the window-frames, and all the materials exposed to the immediate action of the weather, are made of copper; the windows are glazed with plates of polished glass, measuring 29 inches by 18 inches, and ¼ of an inch in thickness, instead of sash panes of crown-glass, measuring only 12 inches by 8 inches, by which so many astragals were unavoidably introduced into the windows, that much of the light was obstructed and lost.