Descriptio theoretica machinae, quae se ipsam movens, aquam ad altitudinem 32 e 34 pedum elevat, quamdiu partes illius notabilem destructionem non acquirunt : et Methodi quomoda fluvii construendi sunt ut in illis ad versus cursum illorum navigari possibile sit / Gotthelf Josepho Schops. [Describing a perpetual motion machine which he invented in 1798, based on the siphon principle. The article was written in Vienna. In Latin. With letter, 1802 Jun 20, Vienna to Le Comte de Buquoy, a l'academie theresienne, Vienna. Holograph signed]