|What fuels produced light?|
The main source of power for the light today is electricity, although in some places they use acetylene gas. For thousands of years before Thomas Edison invented the electric lamp (bulb) in 1879, different fuels were used to illuminate the lamps. First, it was wood and coal for fires, then bales of oakum and pitch, and rows of candles. Later lamps were lit using various fuels --sperm whale oil (produced by cooking the blubber of the whale), lard oil (from animal fat), kerosene (a fuel like gasoline with a petroleum base), etc.
When they first designed a lighthouse with an enclosed lantern room (the original 1696 Eddystone Light in England) it was possible to employ candles for light. This wave-swept lighthouse used 60 candles! Most used far fewer candles that were sometimes arranged in a circular candelabra or a chandelier with two tiers, or on a frame.
Next came spider lamps that consisted of a shallow brass pan containing oil with either four, eight or more wicks usually arranged in a circle, but other shapes such as a rectangle were also used. (Since a spider has eight legs, the first one probably had eight wicks!)
Two very important discoveries occurred in the late 1700s. The parabolic reflector was a bowl-like device with a small oil lamp in the center. The light from the lamp was gathered and focused into a beam. This was similar to putting a mirror behind a flame. Thus the first really efficient lighthouse was created. Think of a flashlight that has a silver reflector behind the tiny bulb to increase the brightness of the light. It is based on the same principle.
The invention of the hollow wick oil lamp (the Argand lamp) resulted in a light that was seven times brighter than a candle. This lamp was used with various types of fuel inside the Fresnel lens until the electric light bulb was invented.
The first lighthouse ever to use electricity in this country was the Statue of Liberty in 1886. Yes, this special symbol of freedom was used as a lighthouse in New York harbor for the first fifteen years of her existence.
|The U.S. Lighthouse Society originally designed this packet to furnish teachers with basic information about lighthouses, their purpose, history, operation and technology in a form presentable to young students. with the society's permission the U.S. Coast Guard Historian's Office is posting this modified version with additional photographs and information.|
The U.S. Coast Guard Historian's Office would like to thank Mr. Wayne Wheeler and the other members of The U.S. Lighthouse Society who produced and distributed the original version of this curriculum.
For more information on lighthouses, teachers and students should contact The U.S. Lighthouse Society, 244 Kearny Street, San Francisco, Ca 94108 or consult the lighthouse web pages on The U.S. Coast Guard Historian's web site.