A Rudimentary Treatise on the History, Construction and Illumination of LighthousesJ. Weale, 1850 - 204 pages |
Other editions - View all
Common terms and phrases
adopted ALAN STEVENSON angle angle of incidence annular apparatus applied Argand Argand burner Argand lamps arrangement AUGUSTIN FRESNEL beam Bell Rock Bell Rock Lighthouse belt burner Catadioptric Zones catoptric light coast colza oil combustion concave cone consideration convex Corduan course curve cylindric diameter dioptric lights direction divergence Eddystone effect equal feet fixed lights flame flashes focal distance frame Fresnel frustum glass height High Holborn ILLUMINATION OF LIGHTHOUSES inches incident inclination instrument joggles John Weale keepers lantern lens lenses less Light-room Lightkeeper luminous means mechanical lamp millimètres mode Northern Lighthouses observer obtained parabolic paraboloïdal paraboloïdal mirrors parallel Pharos of Alexandria placed plane Plate position Principal Lightkeeper prisms produced radius rays reflectors refraction refractors revolving lights rings Robert Stevenson screws shadows shewn shews side sin² Skerryvore spermaceti spherical stone tance tangent tion tower vertical axis waves wick
Popular passages
Page 138 - length, but divided into three or four pieces ; the lower end of each of these pieces for about 1£ inch is opened out into a conical form, about 5£ inches in diameter at the lowest part. When the chimney is put together, the upper end of the bottom piece is inserted about
Page 172 - 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.
Page 18 - 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
Page 168 - When stores of any kind are to be landed for the use of the Lighthouse, the Lightkeepers shall attend and give their assistance. The Principal Lightkeeper must, upon these occasions, satisfy himself, as far as possible, of the quantity and condition of the Stores received, which must be duly entered in the Store-book and Monthly Return-book.
Page 115 - 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
Page 18 - 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,
Page 163 - The Lightkeepers shall keep a regular and constant Watch in the Light-room throughout the night. The First Watch shall begin at sunset. The Lightkeepers are to take the Watches alternately, in such manner that he who has the first Watch one night shall have the second Watch next night. The length or duration of the
Page 107 - 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.