Having talked about navigation at sea quite a bit recently, let’s turn to the tricky bit: the final approach to the port. By now, the chronometer had done its job, your lunar-distance efforts had delivered you safely to within sight of land. From then on, you were on your own.
From the earliest days of mass sailing, coastal authorities such as Trinity House provided navigation aids, and one of the most iconic is the lighthouse. Their bright beams spell out danger or guide ships through safe passages.
Early lighthouses used oil lamps, with reflectors behind to focus the light. But by the 1850s, developments with electric lighting looked promising. This was the era of the arc lamp, in which two carbon electrodes pass electricity across a tiny gap, causing a bright arc of spark.
The light was too bright for domestic living rooms, but perfect for lighthouses, and one of the first to be fitted with electric arc lighting was Souter Point lighthouse, situated just a short walk from my childhood home.
On installation in 1871, Souter’s light was one of the most powerful in the world, visible twenty miles out at sea.
It’s now been taken out of service and is run by the National Trust, and if you want to see the original electric generator (by Frederick Holmes), it’s on show in Making the Modern World, together with the Holmes arc lamp from the South Foreland lighthouse…