During World War II, the Blunts Reef Lightship (LV 100) and the San Francisco Lightship (LV 83) were taken off station and were used as examination vessels for the Port of San Francisco. Their job was to stop all inbound traffic to San Francisco, check the vessel's name, last port of call, and nationality. This information was relayed by radio to Harbor Entrance Control. If all was acceptable to Harbor Entrance Control, permission would be granted, and the lightship would give the entering ship a flag to display for identification on the way into port.
In the annals of lighthouse history, the stories of certain lighthouses are related over and over. Certainly tales of the four Eddystones are known to most who study pharology. Famous construction projects like the Bell Rock and Skerryvore lighthouses of Scotland and California's St. George Reef are often mentioned. The lighthouse afficinado usually knows about the beautiful Corduan of France, or La Coruna (the Tower of Hercules) in Spain, the world's oldest. And of course the Pharos was one of the Seven Wonders of the Ancient World.
In the summer of 1821, the United States assumed control over the old Spanish province of Florida, according to the terms of the 1819 Adams-Onis Treaty. General Andrew Jackson was appointed Territorial Governor in Pensacola, and troops from the United States raised the American flag over the old Castillo de San Marcos in the "Ancient City" of St. Augustine. The civilized section of Florida was in the north; the southern extremities were the haunt of pirates, Indians, and wreckers.
Most lighthouse enthusiasts think that the Fresnel lens was the first lens used in lighthouses. However, that assumption is incorrect in that a number of lenses were proposed and put into use in the years before Augustin Fresnel designed his famous lens. This story will give you information about these early attempts to use lenses to augment the power of lighthouse optics.
The demise of the first tower built to mark the hazardous Minots Ledge offCohasset, Massachusetts, is one of the most dramatic episodes in lighthouse history. Standing on a pile foundation, a relatively new construction technique at that time, the tower succumbed to a gale within 16 months of completion. Two assistant keepers perished. Although the event has been well documented in the past, primary source material recently uncovered by the author in the National Archives, expands and enriches our understanding of this tragic event.
Sea captain Ole Christian Hansen (1850 - 1935) was born in Hombersund. He moved to Skudeneshavn in 1874. In 1879 a bill was passed by the Norwegian government which ordered all vessels bigger than 25 gross tons to carry a mechanical foghorn ready for use. A year later, in 1880, Hansen invented his foghorn for ships. It was distinguished by its low price, forceful sound and solid construction. All over the world it became known as the "Hansalur" or "Skudelur."
The lenticular system of lenses invented by Augustine Fresnel in 1822 initially consisted of six orders (or sizes) of lenses and two types. Prior to Fresnel's "system" numerous parabolic reflectors were hung in tiers around a frame-work in the lantern room. Some lighthouses had as many as reflectors, each with its own lamp tend and wick to trim. Fresnel's system employed but a single light source, one lamp placed in the center (at the focal plane) of the lens. Frensel lenses are like giant beehives of glass prisms set in brass frames.
Over the past century and a half, a slice of lighthouse history on the Staten Island waterfront, just across New York Harbor from lower Manhattan, has seen its fortunes rise and fall. Now, it may again be on the rise—and back in the service of lighthouses.
France had reached a high level of sophistication in the 1790s, especially in the sciences. It was in 1794, that Lazare Carnot, then a high government official, established a very special school for the best scholars within the country. The original name of the school was 'Ecole Centrale des Travaux Publique,' but its name was changed to'Ecole polytechnique' in the following year. The Ecole Polytechnique was under the supervision ofthe Ministry of Defense and was the best technical school in France.
This is the story of one of the most magnificent Fresnel lenses ever proposed and the man who proposed it. The giant in our story is the giant lens proposed in 1892, and our leprechaun is the great Irish inventor John Richardson Wigham. This story deals with Wigham's composite gas burner, his proposal for the hyper-radial lens, and his later development of the giant lens and its associated intensity burner.