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XLI.—Description of a Double Holophote Apparatus for Lighthouses, and of a Method of Introducing the Electric or other Lights
Published online by Cambridge University Press: 17 January 2013
Extract
In the year 1812 I described an apparatus, by which the light of the sun, or of any luminous body concentrated in the focus of an improved lens, could be returned by reflection from a spherical mirror into the same focus, thus increasing the light and heat produced by the cone of refracted rays. The apparatus contained also a double system of lenses and plain mirrors, by which additional beams of light could be concentrated in the same focus.
In 1827 I described the very same apparatus as applied in the dioptric system of lights, the whole of the light which issues from a lamp being thrown into one wide and parallel beam, constituting what has been called a holophote, now in use in every part of the world.
- Type
- Research Article
- Information
- Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 24 , Issue 3 , 1867 , pp. 635 - 638
- Copyright
- Copyright © Royal Society of Edinburgh 1867
References
page 635 note * Edinburgh Encyclopædia, Art. Burning Instruments.
page 635 note † Edinburgh Transactions, 1827, vol. xi. pp. 55, 56.
page 638 note * The method of doing this by lenses, whose conjugate focus is F′, Fig. 1, or by an ellipsoidal mirror, one of whose foci is F, when the spherical mirror (MN, Plate III. Fig. 1, above referred to) is removed, is distinctly shown; but the note describing it was accidentally omitted by the printer.