The thing about lighthouses (that I didn’t get to yesterday) is that they are quite distinctive during the day, but fairly uniform at night. Daytime: different heights, different shapes, different architecture, different colors. Nighttime: light beam. This was all fine and dandy if you just wanted to go out for a brief sail in the harbor. But it wasn’t such a great success for True Travelers. Should you be in the business of long sea voyages, understanding where you are is pretty important.
Joe The Sailor (who in an odd twist of fate was a direct descendent of Joe Neanderthal) tended to get lost a lot which annoyed Mrs. Joe The Sailor. Since Mrs. JTS tended to express her displeasure, and Joe did not enjoy those particular expressions, Joe decided to Do Something About The Situation.
Joe (did I mention that he was a direct descendant of the none-too-bright Joe Neanderthal?) had several ideas for solving the problem. His first thought was to train lightning bugs to blink in unique patterns near the shore. The bugs were quite willing to blink, but tended to stay in their own (random) pattern rather than in Joe’s steady, predictable pattern.
Joe’s second idea was to collect stars and put different stars in each lighthouse. Can you say colossal fail? Can you say “genetics will show”?
Finally, Joe decided to put different numbers of lights in each lighthouse. This wasn’t a terrible idea, but by the 10th lighthouse (which according to Joe’s system should have had 214 lights), the lighthouse keepers revolted and the idea (and Joe) went out the window.
Fortunately, Joe was not left to solve the problem alone.
Augustin-Jean Fresnel (pronounced Frey-nel) was up late one night in 1822 and invented the Fresnel (pronounced Frey-nel) lens. The Fresnel lens is made of hundreds of pieces of specially cut glass which surrounds the bulb. The lens brightens the light from the bulb and focuses it into a directional beam (also known as the Hey!-It’s-A-Lighthouse beam). The Fresnel (still pronounced Frey-nel) lens allows the lighthouse keeper to create an unlimited number of flashing combinations. Unlimited is a big number. Go ahead and count. I’ll wait.