The rotameter and the waterwheel.

The publication imparts information about the personal life and professional sphere of activity of J.A. Segner, Karl Küppers, Maximilian Neu, Hans Bunte, and Felix Meyer, as far as they were involved with the invention of devices for measuring gas flow, especially their involvement in testing the introduction of Rotameters into the medical field.

Introduction of the carbon dioxide absorption method with closed circle breathing into anesthesia practice.

The circle breathing CO2 absorption system for use during acetylene anesthesia was described by Carl Gauss in 1924/1925. The apparatus was manufactured by Drägerwerk of Lübeck. A considerable number of publications on the apparatus employing the closed circle method of CO2 absorption appeared in the medical press soon thereafter.