Notes: "Gustav Starke and Karl Kammerer formed a partnership in 1873 to make and sell scientific instruments, and that partnership lasted until 1917. Starke had previously invented, along with Casper Wetli, the wheel and disk planimeter in 1849. Kammerer was more of a businessman than inventor. Over 1000 planimeters of this design were sold by Starke & Kammerer, this one is No. 310. "
