Lighthouse Technology

Light has been used to guide ships for over 3000 years. The earliest lights were signal fires lit on headlands. Later the fires were maintained on a grate or an iron basket (brazier) on a high location such as a masonry tower or platform. The earliest known lighthouse was the Pharos of Alexandria, which was built around 285 BCE to a staggering height of 130 meters (426 feet). The Pharos was in use for almost 1600 years until it was destroyed by an earthquake in 1302 CE.

The problem with signal fires was that less than 1% of the light could be seen by mariners. There was some improvement when coal was used instead of wood in the braziers in some countries.

A further improvement was the use of a lantern with a flue to get rid of smoke which sometimes obscured the light. The lantern was useful when candles came into use as it kept out much of the wind.

By the 19th century enclosed wick lamps became popular. They burned a variety of oils which produced a brighter light than candles. Some of the oils used were whale, seal, fish, rapeseed and even oil from sheeps’ tails.

In 1846, Dr. Abraham Gesner of Nova Scotia discovered a process whereby kerosene could be produced from coal. It was a discovery that would revolutionize lightkeeping through out the world.