A Rudimentary Treatise on the History, Construction, and Illumination of Lighthouses, Τόμοι 1-3J. Weale, 1850 - 204 σελίδες |
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Συχνά εμφανιζόμενοι όροι και φράσεις
adopted angle angle of incidence apparatus Ardnamurchan Lighthouse Argand Argand lamps arrangement Augustin Fresnel beam Bell Rock Bell Rock Lighthouse belt burner catadioptric catoptric centre of curvature colza oil concave cone convex Corduan course curve cylindric diameter dioptric lights direction divergence Eddystone effect Engineer equal feet fixed lights flame flashes focal distance focus frame Fresnel frustum glass gonal grinding height Henry Law High Holborn horizon illumination inches incident inclination instrument John Weale keepers lantern lens lenses Light-room Lightkeeper luminous means mechanical lamp millimètres mode Northern Lighthouses observed obtained outer parabolic parallel placed plane position practical prisms produced radius radius of curvature rays reflecting side reflecting surface reflectors refraction refractive index refractors revolving lights ring RUDIMENTARY shadows shewn in Plate shews sin² Skerryvore spermaceti stone tance tangent tion tower TREATISE vertical axis whole wicks
Δημοφιλή αποσπάσματα
Σελίδα 184 - The Lightkeepers are to observe that the above general Regulations are without prejudice to any more special Instructions which may be made applicable to any particular Lighthouse, or to such orders as may from time to time be issued by the Engineer.
Σελίδα 38 - It consists of a central belt of refractors, forming a hollow cylinder 6 feet in diameter, and 30 inches high ; below it are six triangular rings of glass, ranged in a cylindrical form, and above a crown of thirteen rings of glass, forming by their union a hollow cage, composed of polished glass, 10 feet high and 6 feet in diameter ! I know
Σελίδα 9 - the sea prevented any one going down to the rock, anxiously looking for supplies from the shore, and earnestly longing for a change of weather favourable to the recommencement of the works. For miles around nothing could be seen but white foaming breakers, and nothing heard but howling winds and lashing waves.
Σελίδα 3 - LAW OF CONTRACTS for all kinds of Buildings, for Employers, Contractors, and Workmen, by David Gibbons, Esq., Author of Treatises on the * : Law of Dilapidations," and on the "Law of Fixtures,** &c.
Σελίδα 5 - successively. The machinery, which causes the revolution of the frame containing the lamps, is also applied to tolling two large bells, in order to give warning to the mariner of his approach to the rock in foggy weather. The erection of the Bell Rock Lighthouse cost £61,331, 9s. 2d.
Σελίδα 135 - with the greatest of those inventors who extend the boundaries of human knowledge, will thus, at the same time, receive a place amongst those benefactors of the species who have consecrated their genius to the common good of mankind ; and, wherever maritime intercourse prevails, the solid advantages which his
Σελίδα 38 - was to that of the seven upper tiers of mirrors of the first order, as 140 to 87. Nothing can be more beautiful than an entire apparatus for a fixed light of the. first order,
Σελίδα 119 - sufficient to discourage us from attempting to improve the visibility of fixed lights in the manner proposed by Captain Hall, even supposing the practical difficulties connected with the great centrifugal force generated by the rapid revolution of the lenses to be less than they really are.
Σελίδα 182 - the premises, at such hours as do not interfere with the proper duties of their office; it being expressly understood. that strangers shall not be admitted into the Light-room after sunset. But no money or other gratuity shall be taken from strangers on any pretence whatever.
Σελίδα 97 - its name. The intermittent light is distinguished by bursting suddenly into view and continuing steady for a short time, after which it is suddenly eclipsed for half a minute. Its striking appearance is produced by the perpendicular motion of circular shades in front of the reflectors, by which the light is alternately hid and displayed. This distinction, as well as that called