Hydrargyrum medium-arc iodide lamp

A hydrargyrum medium-arc iodide lamp is a special kind of lamp that makes really bright light. It's kind of like a big flashlight, but it's so bright that you wouldn't want to look directly at it because it might hurt your eyes.

The way it works is that it has a long tube filled with a gas called mercury and a little bit of iodine. When electricity goes through the tube, it makes the gas light up and give off a really bright kind of light called ultraviolet light.

But ultraviolet light is not very useful for lighting things up because it's too bright and not the right color. So the lamp has a special coating called a phosphor that turns the ultraviolet light into more useful colors like white or blue.

Overall, the hydrargyrum medium-arc iodide lamp is a very powerful and special kind of light that can be used to light up things like streets, stadiums, and even movie sets.