München 2019 – scientific programme

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GP: Fachverband Geschichte der Physik

GP 3: Physicists and their instruments

GP 3.1: Talk

Monday, March 18, 2019, 16:30–17:00, HS 9

Tipping the Scales: Engineer-Captain Johann Adam Cass and His Hydrostatic Balance — •Rebecca Giesemann — Kassel

A hydrostatic balance in an unusual case has been held at the Astronomisch-Physikalisches Kabinett in Kassel for the last 300 years. Bought by Landgrave Carl of Hesse-Kassel, it was not only an object of everyday life, used to measure the salinity of brine, but also a representative item in a princely collection. Handwritten operating instructions by the inventor Johann Adam Cass have been preserved with the balance, including tables with exemplary values. Cass was a resourceful man, advertising his invention across the Holy Roman Empire. There is a three page description of it in Jacob Leupold*s Theatri Statici Universalis of 1726, alongside information on where to buy these wondrous scales: either directly from Cass or from Johann Ernst Elias Bessler, better known as Orffyreus. Orffyreus claimed he found the secret of the perpetuum mobile. In the first half of the 18th Century he thus sparked a discussion among many well-known scholars. But Cass not only was linked to Orffyreus and Landgrave Carl. In 1721 he published a book on the art of engineering, about which a quarrel flared up between him and Ludwig Andreas Herlin, important engineer for the Electorate of Saxony. Taking all this into consideration, the Cass balance serves as a starting point from which an atmospheric picture of the 18th century Inventor*s scene in Saxony, Thuringia, and Hesse can be explored.