Appleton's dictionary of machines, mechanics, engine-work, and engineering : illustrated with four thousand engravings on wood ; in two volumes (1873)
D. Appleton and Company · New York : D. Appleton and Co. · leaf 619
possibility of illuminating light-houses by dioptric means, Fresnel 612 SEA-LIGHTS. quickly perceived the advantage of employing for fixed lights a lamp placed in the centre of a polygonal hoop, consisting of a series of refractors, infinitely small in their length and having their axes irplants…
Mechanical engineering · Mechanics · Engineering
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