Nothing Fishy Here...

before i watched project hail mary i knew exactly 2 things about ryan gosling:

📷 Frans Mäyrä

But in places where big pools weren't feasible, they did everything in their power to reduce the amount of fuel required for the production of salt, because fuel takes a lot of time and effort to collect and drives up costs.

Enter the graduation tower!

The idea is that you take some source of salty water, pump it up to the top of a wooden tower filled with brushwood (typically blackthorn), then let it trickle down, which greatly increases evaporation by maximizing surface area and exposing the water to the wind along the way. When the saltwater reaches the bottom, it's saltier than it was, and you can send it through again until it's reached the point of saturation. If you do this with ocean water, you can reduce the amount of fuel needed by a factor of ten.

Plus it looks and sounds awesome - these were sometimes called thorn towers.

And at the start of the 20th century, when other forms of salt production had skyrocketed in efficiency, the graduation towers began to be used for healthcare, because as you might imagine, the air next to the graduation tower is very salty, more than it is next to the seaside. From what I can find it seems like the main thing it does is thin mucus, though there are a lot of other health claims.