Franz Kessler
Franz Kessler (* 1580 in Wetzlar, † 1650 in Danzig) was a painter, scholar, inventor and alchemist in the Holy Roman Empire.
He wrote a book Different bit hero mehrern partly Secreta or Hidden secret arts about creating codes for encrypted messages, which was published in Oppenheim in September 1616.
In the same year he published a sketch design for a diving bell for a man. Calculations show, however, that it was not functional.
The idea of a mobile one-man diving bell with movable anchor weights was taken up in 1860 by the Viennese painter Eugene of Ransonnet -Villez.
The factory wood saving art from 1618 deals with the improvement of the heat output of ornamental and was published the following year in France.