Discussion

Pharos of Alexandria was known as one of the seven wonders of the ancient world. Built during the reign of Ptolemy II Philadelphus (280–247 BC), it is estimated to have been about 330' tall, more than the length of a football field. Heavily damaged by earthquakes, it remained in use until at least 1323 when it became an abandoned ruin. A castle was built on the site in 1480 using some of the remnants of the lighthouse. In 1994, archaeologists discovered additional remains on the bottom of the surrounding sea.

The oldest surviving lighthouse is the Tower of Hercules, located at A Coruña, Galicia, in north-western Spain. Built in the 1st century A.D. and renovated in 1791, its name until the 20th century was Farum Brigantium. It stands 180' tall, overlooking the North Atlantic. The original version had a spiral staircase winding abound the outside. Signs of it are still visible today.

A much more conventional lighthouse to modern eyes is Boston Light, built in 1716 on Little Brewster Island in outer Boston Harbor, Massachusetts. It was the first lighthouse built in America. The original version, standing 60' tall, was destroyed during the Revolutionary War. It was rebuilt 75' tall in 1783. (This is from the National Park Service. The (trust but verify) Wikipedia article says the original version was 75' tall, too. I'm inclined to side with the historians of the NPS.) It remains the oldest lighthouse in America.

Cracks were found in a survey done in 1809, resulting in the addition of six iron bands around the tower for support. They were replaced with five aluminum bands in the 20th century.

Japan has lighthouses, too. Richard Henry Brunton, a Scotsman specializing in lighthouse design, began building lighthouses known as Brunton's "children" in Japan based on western models in the second half of the 19th century. Before that, Japanese lighthouses resembled castle towers or Buddhist temple bell towers. One of the old-style lighthouses, the Shirasu Lighthouse shown below (48' tall) currently sits on the grounds of Kokura Castle, Kitakyūshū, on the island of Kyūshū. Its original location was nearby, adjacent to the narrow Kanmon strait that separates Kyūshū from Honshū, the largest of Japan's four main islands.

San Diego has its own historical lighthouse at Point Loma in today's Cabrillo National Monument. It was completed in 1855 just a few years after California was admitted to the union. It isn't very tall, but it didn't need to be since the ground it sits on is 422' above sea level. The location seemed ideal, both because of its elevation and because its position marked the entrance to San Diego harbor.

The photo below is from the first floor looking directly upward through the center opening of a spiral staircase. It's here because it looks cool.

The lighthouse, which provided living quarters for the keeper and his family, operated for only 36 years before being replaced by one at a lower elevation. The problem was that it was too high because fogs and low lying clouds frequently made its light invisible to ships at sea.

This is the current Point Loma lighthouse.

Lighthouse technology

Before electricity, lighthouses used fires or burning coal to create light. Boston Light used candles. Beginning in 1784, the standard for over a century for lighthouses became the Argand Lamp, powered by gravity-fed oil of various sorts. I'm not certain, but I think the technology is similar to how Coleman Lanterns work. Argand Lamps produced much brighter amounts of light than earlier methods. Eventually, gas lighting was introduced along with electricity. The latest technology uses LED lighting. I've seen an LED lighthouse at Piedras Blancas Light Station on the California coast north of San Simeon. It emitted periodic, intensely bright flashes of light from an LED about the size of a baseball.

With the introduction of the Argand Lamp, light was steady enough to make optical focusing systems practical. With the use of mirrors and lenses on a rotating base, the modern conception of lighthouses was born. Lenses were heavy, expensive, and inefficient, however. A major breakthrough came with the 1822 invention of the Fresnel lens (pronounced "Fray nel"), named for its French inventor, Augustin-Jean Fresnel. A Fresnel lens is shown below. Its multiple prism system directed nearly all of its light in horizontal directions. Lighting efficiency was boosted to 85% versus the 20% yielded by the best earlier systems.

Its greater efficiency has led to the Fresnel lens being called "the invention that saved a million ships."

On my visit to the Piedras Blancas Light Station, I saw a pre-electric era mechanism for rotating the light/lens platform. It operated much like a cuckoo clock does with weights supplying gravitational energy. Every few hours, the lighthouse keeper needed to raise the weight to keep the mechanism operating.

Regardless of the technology used, every lighthouse today produces a distinctive light pattern. That way, mariners can not only tell that there is a lighthouse nearby but knows which one it is.

Lighthouses in Landscapes

The painting subject this week is lighthouses in landscapes. The photos below provide a few real world examples. Feel free to draw inspiration from any of these for yourself or find others more suited to your taste. Wholly invented landscapes are fine, too.

This first example is fairly typical. It features the Portland Head Lighthouse at Cape Elizabeth, Maine.

This next photo shows the lighthouse at Fanad Peninsula, County Donegal, Ireland.

Next comes the lighthouse at Nugget Point, Otago, New Zealand. The lighthouses in this photo and the one above are little more than tenkei.

To finish, I have three photos of the lighthouse at Foz do Douro, Porto, Portugal. It sits at the end of a jetty on the weather side of a breakwater protecting the mouth of the Douro River. The first simply shows the lighthouse. It isn't a particularly large or remarkable one.

When the Atlantic Ocean acts up, the view of the lighthouse becomes a bit more dramatic.