Fired Up For Fresnel -> The Lens That Changed The World Of Light
I’m always awed by works that combine science and art, and the Fresnel Lens, the ~1-ton piece of multi-prismed glass which tops our lighthouse tower is one of these masterpieces. No single creation has changed the course of lighthouses (and even, our understanding of light itself) more than this amazing lens. In a time when the world believed light was composed of corpuscles (particles), an unassuming, timid and introverted Frenchman believed otherwise. His wave theories, and subsequently his invention of the Fresnel lens revolutionized the world. It’s a story I tell (in very abbreviated version) at the lighthouse & it’s one of the ones I want to pass on to you. Think I have a Fresnel fetish? You bet your fanny I do….
To understand the importance of this invention you have to go back several centuries in time. Prior to the mid-1700’s lighthouses were basically simple towers lit with open flames of either wood, coal fires or candles. Some improvement came about in 1780 with the development of a smokeless oil lamp (the “Argand” lamp) and parabolic reflectors, but the lights were still disappointingly feeble. Ships were either drawn dangerously close to the coast trying to find the weak lights, or never even saw them and shipwrecks were a constant & costly hazard. The problem was the parabolic reflectors wasted far too much of the light. Even the best of them lost at least 1/2 of their light on reflection and they just didn’t reach far enough out.
In 1819 Augustin-Jean Fresnel a slight and “artistically” constituted man was newly appointed to Napoleon’s Commission des Phares (Lighthouse Commission) in France. At this point he had already been working on the wave theory of light for many years and almost immediately realized the light problem could be solved by placing a lens in front of the light and refracting (bending) the light to capture it rather than reflecting it off a mirror in the back. The problem was that to be functional the lens would have to be placed really, really close to the light source and this, in turn, meant it had to be really, really thick, so thick as to be practically useless. More light would be lost going through the lens than even the old reflectors.
The resolution of this tricky problem was the key to everything.
Fresnel had the inspiration of breaking up the single curved surface into multiple, smaller prisms which would act like a giant lens when put together. He immediately started work on the concept and in 1821 was able to demonstrate his first success. By 1823 the world’s first Fresnel lens was installed at the Cordouan Lighthouse in southwestern France and the brilliance of the new light was astonishing. It took another ~25 years, an industrial revolution (basically the introduction of the steam engine) and the brother of Fresnel (who carried on his work after his death) to perfect Fresnel’s original vision, but the final lens was a masterpiece. By the mid 1800’s some version of the Fresnel lens was glowing at almost every lighthouse in Europe, parts of Africa, Asia and South America.
All except America…
In America thanks to a stingy, sourpuss (he looked it too) accountant by the name of Stephen Pleasanton the adoption of the new device was resisted until 1850 and even a bit further after that. A rather juicy story of internal politics, money & backhanded subterfuge delayed Pleasanton’s firing, but once he was gone the newly appointed Lighthouse Board went full force and by 1859 there was a Fresnel Lens in almost every lighthouse in America. Fresnel’s vision of light was complete.
There is SO much more to this story, including the importance that lighthouses (and the Fresnel lens) played in the Civil & World Wars, the stories of mercury baths (some lighthouse keepers literally went nuts), and how Fresnel lenses are still used today (in theater lighting, for example) and it’s all brilliantly written in the book “A Short Bright Flash“, which I highly recommend for all you aspiring and converted lighthouse nutters. Frikkin’ fascinating story!
But beyond the story are the original Fresnel lenses themselves. There are so few of them left, and even fewer in actual operation and even fewer that you can stand right next to. At Cape Blanco you get it all -> an operational, amazing Fresnel lens that you can stand within a foot of and get mesmerized by the moving rainbows writhing within her perfectly-formed prisms. Most people who come here are completely amazed once they get up close and can barely fathom the fact that a 1000 watt bulb only a few inches high can cast a light 26 miles to sea. That’s the beauty of the design, baby, as I so often tell them (or a little more formally anyway). On busy days I’ll try and give folks as much time as possible by the lens ‘coz I know how cool it it. On quiet days I’ll sometimes stand up there by myself & lose myself in her beauty, just because I can. It’s the lens that changed the world of light and if you ever get the chance, you’ve got to come see one.
Oh, yeah I definitely have a fetish 🙂
P.S. Believe it or not it’s been 9 years since Paul & I gave up the daily 9-5 grind in search of an alternative lifestyle. To mark the day, Paul’s updated his popular Recipe For A Happy Retirement post. This great little post combines our thoughts on what “retirement” means and what it takes financially, socially, mentally and physically to make the switch. Go have a read!
Gah! It takes me so long to get through your post, ’cause I get so sidetracked! I could have kept reading about the lenses and moseyed off to other sites, but I’d be here all night.
I totally ‘get’ your little bit of a fetish.
Carry on!
LOL….takes me ages to write blog posts like this ‘coz I get totally distracted myself. The history is fascinating.
Nina
Question. This is our first westward adventure with a puppy in August/September/October in the desert regions of Idaho, California, Arizona, and New Mexico. How do you protect those puppy paws or don’t you have any problems – summer or winter?
We actually don’t use anything for the paws. Polly has pretty tough paws and adapts very fast to just about anywhere she goes. Plus, she’s a pretty careful doggie (rarely, if ever, gets caught in cactus). I know some folks who use paw-protectors (booties), but we’ve never tried them.
When we first get to the desert (say, after a longer period in grassy areas) we’ll do shorter hikes until her paws toughen up, but after that we don’t do much of anything at all. We DO carry a pair of tweezers when we hike in case anything gets stuck that we need to remove and we do NOT hike in sand/desert if it’s overly hot.
Hope that helps!
Nina
Definitely fascinating stuff. I worked in ophthalmology and we prescribed Fresnel prisms for double vision. They are thin, transparent plastic sheets that can be cut to fit and stuck on eyeglass lenses. The prismatic effect moves the two images together to eliminate the double vision.
Of course, this is nothing like the enormous Fresnel lenses at the lighthouse!
Indeed Fresnel lenses are still used in glasses today. Did not know you worked in ophthalmology….interesting!
Nina
Fascinating stuff. The fact that it’s a passion for you makes the writing so much more…illuminating (could not resist).
BTW, I know YOU know, but the 26 miles is more related to the horizon and earth’s curvature. That sucker would be seen WAY further than 26 miles if the earth were still flat. 🙂
Yup, the darn curvature of the earth always gets in the way. Lots more cool science around all this, but only so much space in a blog post 🙂
Nina
Nina,
I don’t comment much here…but..I always do when you’re talking about lighthouses. I saw my first Fresnel lens in 1967..been a fan ever since. The imagination/ability it took to even design a Fresnel lens…..blows my mind. One of the greatest and most important inventions….ever. The lens at Cape Blanco is gorgeous!
Nice to know I have some fellow hardcore lighthouse lovers out there 🙂 I too have been fascinated by Fresnel lenses ever since I first saw them. Hard to say which one is my favorite, but the multi-faceted lens at the Maritime Museum in Westport, WA and the red/white beauty at Umpqua River, OR rank high on my list. And of course the one here at Cape Blanco is special for having been in continuous operation for so long.
Nina
Loved the lighthouse tour, but sorry to have missed you! Thanks for this article. We have moved on down the coast to Eureka, CA. The weather at Cape Blanco was so much nicer than we are now having here, lots of Humboldt Fog!
Sorry we missed you too (we’ve had a few days off from work recently), but glad you made it out to the lighthouse. Don’t feel too bad about the weather. We’re seeing grey and fog here today too.
Nina
You are right about the theatrical use, we had a large collection of them for use during Torchlight Tattoo, and Spirit of America programs that we presented to the Public at the Jefferson Memorial, and Capitol Center back when I was with the Old Guard, serving with their commo section which included theatrical lighting and sound divisions, that was back in ’76 so I would imagine things have changed since then.
Not much has changed. I ran a theatre company back in 2007 and we had Fresnel lenses there too.
Nina
Do you have a Fresnel lens on the back window of The Beast?
Ha no, but Fresnel Lenses are still commonly used in taillights and turnlights, so we may well have one back there (I’ll have to go check).
Nina
Apparently the popular “wide angle” stick-on window lenses are fresnels with a negative focal length.
That lens is indeed a gorgeous piece of work. Your photos are wonderful; I can see why you’re captivated. Very interesting story, too — I enjoyed the colorful personalities of the players.
It’s hard not to get captivated in the history and beauty of these things. And it sure is a fun hobby.
Nina
:::sigh::: A post after my own heart. From the complexity of the art form, to the simplicity of the guiding light, I too am smitten. I particularly love your panorama shot with the bulb. So much going on in that one photo! I recently counted…I made it to 17 this summer…not all with Fresnels of course, but still fun looking back at the different personalities of each one. No surprise, we share the same favorites. Thanks for the great “Fresnel Fix!”
Your Nutter Friend
17 is a good, solid number. We managed 10 this year, of which 2 were with you! Definitely some good memories there.
Nina
Awesome writeup! Thanks so much for sharing!
I love Fresnel lenses and am always so sorry to see them on display rather than working. Lucky lucky you and cheers for the lighthouse and its decision makers. Your pictures are fantastic. I just love that second one with the “candle”. Great post. Had to laugh when I clicked on Mr. Sourpuss. Guess I’ll have to read the book, thank you very much for putting me on to it, in order to find out why in the world he was so opposed. Do they take singles as guides at Cape Blanco? If David is ever able to travel to Oregon we really really have to do this.
Yeah, Mr.Sourpuss was basically just a stingy accountant and really didn’t see the point in spending more for lenses when he could stick with the cheaper reflectors. Clearly, he knew nothing about shipping.
YES, they do take singles here.
Nina
WHOOOPIEEEEE!
I too have been fascinated by the Fresnel lens. I love the prisms and rainbows. Maybe that’s why I also like crystals hanging in my sometimes sunny windows. A great history.
Oh I’m so with you on crystals. Love little rainbows dancing around my room.
Nina
I always love books that answer the question “How in the world did someone think of THAT?” These large sculptures are so beautiful one often forgets the huge number of lives saved by their invention. Love your nerd posts – with your theatrical background and your love of science your tours must be so fun. Loved Paul’s updated post – congratulations to the three of you on your 9-year anniversary!
The FIVE of you – my apologies to the kitties for my momentary lapse 🙂
I’m happy to hear I have some “nerdy” followers out there. And no worries about the three or five. We come as a “pack” 🙂
Nina
I love Fresnel lenses too – when I first saw one working in stage lighting, I couldn’t stop wondering about it! Thanks for another fun, informative post, and a good book to add to my ever-burgeoning reading list. 🙂
I love that Fresnel’s are still used today, not only in theatre, but also in taillights, turn-lights and other places. His invention lives on!
Nina
Saw that lens up close this Summer, too bad Deng kids vandalized some of it.
BTW Jodee are we related? French Canadian? New Englander?
Thankfully the vandalism that happened here was able to be repaired (and the folks who did it were caught and fined). The lens up at Cape Meares was not so lucky. Don’t know why anyone would want to destroy these pieces of art.
Nina
Loved the information on the lens – as honestly I’m not a patient reader of signs and probably read some of that in one of my many lighthouse visits. Nice job explaining it best and with enthusiasm!
Glad you liked the post!
Nina
I have a question, been following your blog for quite a while now and I really enjoy it. I get the weekly digest which makes me look forward to the Monday postings. Now to my question. When crossing the border on I-5 in a motor home do they still restrict fruits and vegetables and do they do an inspections? We have never gone south into California in our motor home and I would like to know what to expect. Thank you for your time. Connie
Yup, CA has agricultural inspection stations at all the border points. Typically they stop you and ask if you are carrying any fruits or vegetables. If you say “no” they usually just wave you through. They rarely do a physical inspection, but they absolutely have the right to stop you and do so, so you should be aware of what you can and cannot bring into the state. For example, no citrus !
Here’s a complete guide for you:
http://www.cdfa.ca.gov/plant/factsheets/BringingFruitsVeggies_to_CA.pdf
Nina
Love this post, Nina! My great grandfather built Old Mackinac Point lighthouse in 1892, and I worked on a State of Michigan committee to get it reopened. Diana and I visited the USCG Ninth District office in Cleveland a number of years ago, and OMPL’s fourth order lens was on display in the admiral’s office. Even though it was cool that it stood guard over the Rock and Roll Hall of Fame, it was great that our US senator was able to pull strings and get it back to its’ rightful home in Mackinaw City, MI.
So glad to see you and Paul guarding Cape Blanco, and we “get” just how significant a working lens really is. Nothing like it on earth. We were fortunate enough to tour Heceta Head at night on a special tour. That pinwheel of light extending out over the Pacific literally took our breath away.
Thanks for sharing this with us!
Jim
Wow! I have never met anyone who had a history in the building of a lighthouse. That is so amazingly cool! We’ve never been to Old Mackinac Point, but I’ll be sure to add it to our ever-growing list…and now I have a link there!
Thanks so much for sharing your story!
Nina