. Lighthouse construction and illumination; . he originated, by first referringto his central burner system. In all lighthouses priorto 1822 the mode of getting up the required power wasby employing a sufficient number of separate reflectors,each of which (unless we except Bordier Marcets mirror)required its own separate lamp. But Fresnel placed in thecentre of the apparatus a single lamp, which had four con-centric wicks, and was fed with oil by a pump workedby clockwork. Surrounding tliis burner was a stationarycylindric refractor for a fixed light, and revolving annularlenses for a revolvin
. Lighthouse construction and illumination; . he originated, by first referringto his central burner system. In all lighthouses priorto 1822 the mode of getting up the required power wasby employing a sufficient number of separate reflectors,each of which (unless we except Bordier Marcets mirror)required its own separate lamp. But Fresnel placed in thecentre of the apparatus a single lamp, which had four con-centric wicks, and was fed with oil by a pump workedby clockwork. Surrounding tliis burner was a stationarycylindric refractor for a fixed light, and revolving annularlenses for a revolving light. The mechanical lamp, as it is called, was designedjointly by Fresnel, Mathieu, and Arago, and will be after-wards more fully described. FKESNELS DIOPTRIC COMBINATIONS. 67 Feesnels Combinations of his Optical Agents. 15. Catadioptric Fixed Light.—This apparatus (Figs. 35,36) consists of the central lamp, surrounded by a cylindrico ,. refractor E, while above and be- low are zones of silvered mirrorA, similar in j)rofile to Bordier.
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Keywords: ., bookcentury1800, bookdecade1880, bookpublisherlondo, bookyear1881
