For greater security in all such exposed situations as the Eddystone or the Bell Rock, _four_ keepers are provided for one light-room. One of these is always ashore, on leave, with his family, and the other three are on guard in the lighthouse, so that, in the case of the illness of one light-keeper, an efficient establishment of two keepers for watching the light may remain. The following interesting details we borrow verbatim from Mr. Alan Stevenson:[24]— [24] Alan Stevenson, “On Lighthouses,” Weale’s Series, pp. 169, 170. Each of the two (or three) light-keepers has a house for himself and family, both being under a common roof, but entering by separate doors. The principal keeper’s house consists of six rooms, two of which are at the disposal of the visiting officers of the Board, whose duty in inspecting the lighthouse or superintending repairs may call them to the station; and the assistant has four rooms, one of which is used as a barrack-room for the workmen who, under the direction of the foreman of the light-room works, execute the annual repairs of the apparatus. The greatest care must be bestowed on securing the utmost cleanliness in every detail connected with a lighthouse, whose optical apparatus is peculiarly sensitive to the effect of dust. For this purpose covered ash-pits are provided at all the dwelling-houses, in order that the refuse of the fireplaces may not be carried on “the wings of the wind” to the light-room; and, for similar reasons, iron floors are used in the light-rooms instead of stone, which is often liable to abrasion, and all the stonework near the lantern is regularly painted in oil. If, in all that belongs to a lighthouse, the greatest cleanliness is desirable, it is in a still higher degree necessary in every part of the light-room apparatus, without which the optical instruments and the machinery will neither last long nor work well. Every part of the apparatus, whether lenses or reflectors, should be carefully freed from dust before being either washed or burnished; and without such a precaution the cleansing process would only serve to scratch them.