极限集邮网

标题: 朴次茅斯海港 (Portsmouth Harbor) 灯塔 [打印本页]

作者: ngsunyu 时间: 2014-3-20 07:55
标题: 朴次茅斯海港 (Portsmouth Harbor) 灯塔
Portsmouth Harbor Lighthouse is located within Fort Constitution (宪章堡)
in New Castle (新堡), New Hampshire (新罕布什尔州), USA.
The station was established in 1771 and was the 10th of 11 light
stations established prior to the American Revolution. The first tower
was a shingled wooden structure with an iron lantern and copper roof.
Its light source was three copper oil lamps.
The first tower was replaced in 1804 by an 80-foot (24 m) octagonal
wooden tower approximately 100 yards (91 m) east of the 1771 tower. In
1851, twenty years after the establishment of Whaleback Lighthouse,
the tower was shortened to 55 feet (17 m). Three years later, in 1854,
the tower was fitted with a Fourth (4th) Order Fresnel Lens.
In 1878, a new 48-foot (15 m) cast-iron, brick-lined lighthouse tower
was erected on the same foundation as the 1804 tower. When the new
tower was completed, the surrounding remains of the 1804 tower were
removed.
The current light is a fixed green signal that is visible for 12
nautical miles (22 km; 14 mi). The light is made green by an acrylic
cylinder that surrounds the lens.
(http://en.wikipedia.org/wiki/Portsmouth_Harbor_Light)

Portsmouth Harbor lighthouse 13-7-2013 New Castle ed Harry Winebaum News.jpg (202.36 KB, 下载次数: 71)

欢迎光临极限集邮网 (http://chinamaxicard.com/)