Oh for the days of old technologies! Oh for a music-playing systems that allows you to hear more than a fog-horn accompanied by nervous timepieces!
And oh (while I'm here) for a phone that isn't so egotistical that it requires constant stroking!
So, to the foot-candle. It measures brightness. It's something to do with the brightness cast by, yes, a candle over a square foot of surface (a foot is just over 30 centimetres. A foot is said to be based, mysteriously, on the length of Henry I's arm. Or Charles II's foot. Or something.).
Most excitingly, an area illuminated by a foot-candle will reflect light...or have a luminance if that's different...equal to a foot-lambert...
...oh dear. I never really got this technology stuff, did I. Not even when it was described in terms of candles.
Whatever they are.
Things to feel nostalgic about today: foot-candles and foot-lamberts. Candle comes from the Old English candel, from the Latin candēre, to be white or glitter. A lambert is named after Johann Heinrich Lambert (1728 - 1777). My Collins dictionary says he was German, and Wikipedia says he was Swiss, but he was born in Mulhouse, which last time I looked was in France. Anyway, he was a mathematician and physicist.
Lambert, oh-so-fittingly, means bright land.