Point Reyes Light

The Point Reyes Light sits at the bottom of a roughly 30-story staircase, accessible after a short walk and a long drive through Point Reyes Park. I’d suggest bringing some cheese from the Cowgirl Creamery in Point Reyes Station for the journey.

According to the park website, it’s the windiest point on the Pacific coast, and the second foggiest point on the continent. It’s also a pretty cool example of some beautiful old technology: the Fresnel lens.

I’ll talk through what that means and why it’s cool in a second, but first, here’s a picture of the lighthouse that Maira took:

Doesn’t look so hot from the outside, but don’t judge a lighthouse by it’s decaying exterior!

The Fresnel Lens

In order to send light as far as possible in the foggy, windy night, lighthouses want to focus as much of the light from their lamp as possible into a concentrated beam. Early lighthouses used carefully placed mirrors to reflect light from a flame, but ended up scattering much of it.

Did you know the word lens comes from the latin for lentil because they share a similar shape? Pretty cute.

Anyway you want a big glass lentil to help focus all of that light into a nice coherent beam that you can shoot out into the horizon. Unfortunately, lighthouses are big and tall, so in order to capture enough light to reach the horizon some 20 miles away, you’d need a pretty huge, unwieldy, difficult to manufacture piece of glass.

The Fresnel lens solves this problem by.. splitting up the lens into much smaller sections with the right level of convexity. Check out this (public domain!) image from Wikipedia:

That lets you get the same effect as a convex lens (all of the light is turned horizontally), but with a much thinner, lighter, and easier to manufacture design.

The Point Reyes Light

Not only is the Point Reyes Light a Fresnel lens lighthouse, it’s a “first order” Fresnel lens, which means it was the largest kind manufactured. And not only that, it’s a fancy, French “first order” Fresnel lens (a FFFOFL). Specifically, it was designed in part to be displayed at the 1867 Paris World’s Fair. As such, it’s pretty ornate.

I’ll note that I’m impressed partly because the thing seems so precisely designed and machined in a pre-CAD era—the architects and designers probably had nothing more sophisticated than hand drawings and careful use of tools to get the lighthouse right. The result is a beautiful Jules Vernian slice of technology—a real glimpse of a beautiful paleofuture that never came to be.

But all that impressive engineering wasn’t enough to keep the old lightkeepers entertained forever. The exhibit there now goes out of it’s way to depict how horrible this job was. I’ll dodge the need to talk about all of the consequences of automation here, and just say this is one job that won’t be missed.

Lastly, as with any decaying structure, I found a bunch of really nice textures. Mmmm.

Okay! Cool.

If I get enough time, I’ll write a little about a different Point Reyes Light, the local newspaper by that name. They exposed a strange Californian cult called Synanon that operated out of the Tomales Bay area on the site of a former trans-Pacific radio receiving station that we also got a chance to visit. Spooky!