Reading about bulbs lead me on a journey and I somehow stumbled upon limelights (aka oxyhydrogen bulbs), which was the original theater lighting 'bulbs'. Basica

Reading about bulbs lead me on a journey and I somehow stumbled upon limelights (aka oxyhydrogen bulbs), which was the original theater lighting 'bulbs'. Basically, you can direct a torch over a block of lime (or a cinder-block I guess) and it will become extremely bright. Could only find one video of the effect: https://www.youtube.com/watch?v=wheumkzDslA https://www.youtube.com/watch?v=wheumkzDslA