“Let us now return to the spiral staircase which has brought us thus far, and which will carry us at once to the portion of the edifice which is more particularly destined to fulfil the special purpose for which the tower is designed. The eighth storey contains vessels of oil, glasses, revolving lamps, some admirable instruments intended for meteorological observations, a thermometer, barometer, and chronometer. Here the spiral staircase terminates in a flattened arch, which supports a slender pillar, cut into steps, which are the only means of communication with the watch-tower above, in which the men take it by turns to keep guard every night. You will be surprised on looking round to perceive that this apartment is coated with different coloured marbles, which line the walls and vaulted roof, and even cover the floor. But this luxury, which may appear to you so much out of place, has been introduced from necessity. The apparatus for lighting the building enters the room through a circular aperture in the ceiling, and hence the most extreme cleanliness becomes necessary, which could alone be obtained by the aid of perfectly polished surfaces.” The tenth and last flight of steps brings one beneath the cupola, and to the machinery by which a light of the first order is maintained. CHAPTER XII. THE LIGHTHOUSE (_concluded_). Lighthouses on Sand—Literally screwed down—The Light on Maplin Sands—That of Port Fleetwood—Iron Lighthouses—The Lanterns themselves—Eddystone long Illuminated with Tallow Candles—Coal Fires—Revolution caused by the invention of the Argand Burner—Improvements in Reflectors—The Electric Light at Sea—Flashing and Revolving Lights—Coloured Lights—Their Advantages and Disadvantages—Lanterns obscured by Moths, Bees, and Birds.