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"Holophotal Catadioptric Apparatus Revolving round a Central Flame.—If in place of Fresnel's compound arrangement of trapezoidal lenses and plane mirrors there are substituted mirrors R, R generated by the revolution of a parabolic profile round a horizontal axis, all the light will be at once sent out in parallel beams by them and the lenses L, and the apparatus is therefore geometrically perfect, but metallic instead of glass agents are still employed." —The Encyclopedia Britannica, 1910

Holophotal Catadioptric

"Holophotal Catadioptric Apparatus Revolving round a Central Flame.—If in place of Fresnel's compound…

"Holophotal Fixed Light varied by Flashes.—Fresnel's double agents are here also dispensed with by the single agency of panels of fixed light apparatus p', p' and cylindrical refractors L', L', alternating with panels of holophotal apparatus p, p, L, L, both of which revolve together round the central burner." —The Encyclopedia Britannica, 1910

Holophotal Light

"Holophotal Fixed Light varied by Flashes.—Fresnel's double agents are here also dispensed with by…