Stadimeter

A stadimeter is a tool that helps people measure the distance between two things that are far away from each other. It's like a ruler, but instead of measuring things that are close to you, it measures things that are really far away, like ships or planes in the sky.

Here's how it works: When you look through the stadimeter, you'll see two images of the same thing that you want to measure the distance of. You turn the knob on the side of the stadimeter to make the two images come together and line up perfectly. Once they're lined up, you can read the distance measurement on the scale on the side of the tool.

So, if you wanted to measure how far away a boat was from the shore, you would use the stadimeter to line up two images of the boat and then look at the scale to see how many meters or feet away it is. This can be really helpful for people who need to know the distance of things that they can't get up close to, like military personnel or sailors.