ClipArt ETC
"Catadioptric Fixed Light.—This apparatus, in which a central burner is used, consists of a dioptric cylindric refractor with zones of silvered mirror above and below similar in profile to Bordier Marcet's reflector. By the adoption of the refractor the whole of the wasteful divergence which occurs in Marcet's reflector is prevented. We have here a geometrically perfect combination, but it is not so physically, because metallic reflexion is used. This physical defect Fresnel obviated in his next design." —The Encyclopedia Britannica, 1910

Catadiopteric Light

"Catadioptric Fixed Light.—This apparatus, in which a central burner is used, consists of a dioptric…

"Catadioptric Fixed Light.—This apparatus, in which a central burner is used, consists of a dioptric cylindric refractor with zones of silvered mirror above and below similar in profile to Bordier Marcet's reflector. By the adoption of the refractor the whole of the wasteful divergence which occurs in Marcet's reflector is prevented. We have here a geometrically perfect combination, but it is not so physically, because metallic reflexion is used. This physical defect Fresnel obviated in his next design." —The Encyclopedia Britannica, 1910

Catadiopteric Light

"Catadioptric Fixed Light.—This apparatus, in which a central burner is used, consists of a dioptric…

"First Application of Total Reflexion to Fixed Lights. In this apparatus Fresnel substituted his totally reflecting prism p and lens R for Marcet's reflector, and thus distributed the whole light equally over the horizon by means of dioptric agents alone. This was the first application of total reflexion to lighthouse apparatus, and this beautiful instrument continues till now in universal use." —The Encyclopedia Britannica, 1910

Dioptric Light

"First Application of Total Reflexion to Fixed Lights. In this apparatus Fresnel substituted his totally…

"Fresnel's Revolving Light. —In this form of revolving light the central burner is surrounded by annular lenses L, and a compound arrangement of inclined trapezoidal lenses L' and plane silvered mirrors M. The inclined lenses fit closely to each other and form a pyramidal dome, and the light, intercepted by them, is sent upwards in inclined beams until, falling upon the plane mirrors M, it is sent outwards in horizontal parallelized beams. All these optical agents are made to revolve round the central lamp, and the sailor receives a full flash when the axis of one of the emerging beams passes his eye, and as soon as it passes him he is in darkness until the next beam comes round." —The Encyclopedia Britannica, 1910

Fresnels Revolving Light

"Fresnel's Revolving Light. —In this form of revolving light the central burner is surrounded by annular…

"Fresnel's Revolving Light. —In this form of revolving light the central burner is surrounded by annular lenses L, and a compound arrangement of inclined trapezoidal lenses L' and plane silvered mirrors M. The inclined lenses fit closely to each other and form a pyramidal dome, and the light, intercepted by them, is sent upwards in inclined beams until, falling upon the plane mirrors M, it is sent outwards in horizontal parallelized beams. All these optical agents are made to revolve round the central lamp, and the sailor receives a full flash when the axis of one of the emerging beams passes his eye, and as soon as it passes him he is in darkness until the next beam comes round." —The Encyclopedia Britannica, 1910

Fresnels Revolving Light

"Fresnel's Revolving Light. —In this form of revolving light the central burner is surrounded by annular…

"Fresnel's Revolving Light. —In this form of revolving light the central burner is surrounded by annular lenses L, and a compound arrangement of inclined trapezoidal lenses L' and plane silvered mirrors M. The inclined lenses fit closely to each other and form a pyramidal dome, and the light, intercepted by them, is sent upwards in inclined beams until, falling upon the plane mirrors M, it is sent outwards in horizontal parallelized beams. All these optical agents are made to revolve round the central lamp, and the sailor receives a full flash when the axis of one of the emerging beams passes his eye, and as soon as it passes him he is in darkness until the next beam comes round." —The Encyclopedia Britannica, 1910

Fresnels Revolving Light

"Fresnel's Revolving Light. —In this form of revolving light the central burner is surrounded by annular…

"Fresnel's Revolving Light. —In this form of revolving light the central burner is surrounded by annular lenses L, and a compound arrangement of inclined trapezoidal lenses L' and plane silvered mirrors M. The inclined lenses fit closely to each other and form a pyramidal dome, and the light, intercepted by them, is sent upwards in inclined beams until, falling upon the plane mirrors M, it is sent outwards in horizontal parallelized beams. All these optical agents are made to revolve round the central lamp, and the sailor receives a full flash when the axis of one of the emerging beams passes his eye, and as soon as it passes him he is in darkness until the next beam comes round." —The Encyclopedia Britannica, 1910

Fresnels Revolving Light

"Fresnel's Revolving Light. —In this form of revolving light the central burner is surrounded by annular…