The Chemex was made by a chemist.
Peter Schlumbohm, German-born, refugee in New York, designed it in 1941 from a single piece of laboratory glass with a folded paper filter and a wooden collar tied with a leather thong. It looks like an Erlenmeyer flask grown up to hold a morning. The Museum of Modern Art keeps one in its permanent collection. So does most of the specialty coffee world.
What the Chemex does is filter clean. The paper is thick — heavier than any other brewing paper — and it removes more of the oils and fines than other methods. The cup that comes is clear in a way few coffees are: tea-bright, articulate, almost transparent in flavor. You taste the bean and the bean only.
It is the slowest of the methods in this app. Make a Chemex when you have the time.