"During the second half of the 19th century, mathematical models for use in teaching became very popular. One of the most prominent producers (known as publishers) ...
of models for commercial use was the firm of Ludwig Brill of Darmstadt, Germany. In 1899 Martin Schilling took over and expanded the business from Brill. The kinematic models in the Smithsonian’s collection housed at the National Museum of American History were produced by the firm of Martin Schilling. His firm produced numerous types of mathematical models, including twelve kinematic models of which the Smithsonian presently has ten. Originally located in Halle, Germany, the firm moved to Leipzig sometime after 1903. The kinematic models were designed by German mathematician Frederick Schilling (1868—1950), professor of mathematics at Göttingen, who became the scientific director of the company." - https://www.si.edu/spotlight/kinematic-models, 15.05.2022
