The Different Eras 1845 – 1860: The Early Years 1860 – 1900: Spirometer Designs Evolve 1900 – 1940: The Spirometer Finds New Uses 1970 Onwards: The Rise of the Electronic Spirometer 1860 – 1910: Treating Lung Disease with Spirometers 1890 – 1930: Penny Arcade Spirometers