Jane and I got a permit to climb the Boston Light. If ever there was a nineteenth-century French genius (given the place and time, to use the term seems reasonable) it was Auguste Fresnel, the French theorist of light who defined wave theory and invented the lens named after him in the 1820s. As I'm sure you know, lighthouses (at least, good ones) use the Fresnel lens. The one in the Boston Light was installed in 1852, and is still functioning flawlessly: a 1,000 watt bulb magnified so as to be visible for 27 miles.
We landed on the island (Little Brewster, one of the outermost in the harbor), and climbed right up to the light itself, the lens slowly revolving inches away from us to produce one flash every ten seconds. This light has guided us many times when approaching the harbor from the wild waters beyond, a presence infinitely more comforting than anything a GPS system can provide. There has been a light on Little Brewster (a pocket handkerchief of an island) since 1716, and the present lighthouse dates from the 1780s, the British having destroyed its predecessor during the evacuation of Boston in 1776. It is the only crewed lighthouse remaining in the country, operated by the Coast Guard, and the present keeper is a woman—the first—named Sally Snowman. Her husband, mark you, is her assistant.
To have steered for the light under sail on the open ocean, and then to have been able literally to kiss it (though one mustn't touch the lens, so I didn't) is a remarkable exercise in the consecutive perception of distance, proximity, and internal perspective. This beats all the art shows in Boston.