Mobile Bay
Lighthouse Information and Photos

Mobile Middle Bay 
	Lighthouse lens
Mobile Middle Bay Light

The Fresnel Lens

The Fresnel Lens was named for Augustin Jean Fresnel, a French Physicist who, in 1828, demosnstrated wave theory of light and changed the entire world's lighthouse illumination to the Fresnel System. The Fresnel lens collected the light radiated at random from a small light source and directed the rays to the horizon.

Whale oil was the first fuel used and the lighthouse tenders worked in shifts making sure that the lamps did not ho out and smoke the lens. In later years kerosene was used and eventually they were converted to electricity.

The Fresnel Lens in the Sand Island Lighthouse magnified a 1,000 watt bulb so that the ten-second flash could be seen 17.5 miles away. The lens in the Mobile Point Lighthouse was visible 10 miles away.

The Lighthouses

The Middle Bay Lighthouse was constructed in 1885 and is located at the mid point of the Mobile ship channel. On December 1, 1885 the lighthouse was commissioned and began operation with a single fourth-order Fresnel lens (see lens above) inside an iron lantern.

Mobile Point's first lighthouse was a 55 foot brick tower built in 1822. The fourth-order lens with twenty-one lamps and fourteen-inch reflectors was visible from twelve to fourteen miles at sea. Because Mobile Point's light was equivalent in power to a common harbor light the Lighthouse Board made the decision to erect a new seacoast light with a more powerful first-order lens on Sand Island. In 1873 a new second-order lens was placed in the lighthouse and remained, lighting the way for ships seeking to enter Mobile Bay, until it was removed in 1971. (See lens on right).

 Sand Island Light 
	house Lens
Sand Island Light
Mobile Point 
Mobile Point Lighthouse (1872-1966)

In August of 1864 the brick light tower of the Mobile Point light house became the target for Union artillery during the siege of Fort Morgan and the lighthouse had suffered irreparable damage. In late 1872 work began on the new Mobile Point light tower. The Lighthouse Service shipped the iron lattice-work tower to Mobile Point in November. The tower was erected during January of 1873 and the 1858 fourth-order fesnel lens was placed in the lantern house. On February 15, 1873, the fixed red beacon was lighted for the first time. It was extinguished in 1966 and was replaced by an automated rotating beacon. (see Photo on Left)

Special thanks to the Fort Morgan Historical Site. The above information was prepared by Michael Bailey for the Fort Morgan State Historic Site. Photos are by Ted Brown. Unauthorized duplication of any materials from this page is prohibited without written permission.

Inbound ship approaches Sand Island Lighthouse South of Mobile Bay in the Gulf of Mexico.

Gas Drilling Platform located just North of Fort Morgan in Lower Mobile Bay

View of sunrise in Gulf of Mexico near Sand Island.

[Pensacola Maritime Site Home]

Since November 7, 1999