When was Fahrenheit discovered?

It wasn't really discovered, it was contrived by a German "scientist"(?) named Gabriel Fahrenheit. He took a glass tube filled with Mercury, and observed the height of the mercury in the column when water froze. He marked that. Then he marked the tube (it was outdoors) on what he determined to be the coldest day of the winter. He marked that, and called it "zero" - the "coldest it ever got". Using very small increments for "accuracy"(!) he determined that water froze at 32 degrees above "zero". He continued the same increments up the scale. It does have a logic to it, but not on any true scientific principal.