Von Basch Sphygmometer In 1881, Samuel Siegfried Karl Ritter von Basch invented the sphygmometer. A mercury or water-filled rubber ball, connected to a manometer, was pressed against the radial artery until the pulse was obliterated. The blood pressure was then estimated using the manometer. Palpation was used to determine when the arterial pulse disappeared. So indeed, contrary to popular belief, the early devices were filled with liquid (water or mercury) and not air. It is only in 1889 that Potain, in France, improved all the compression devices by replacing water and mercury in the devices with air, substantially improving their accuracy. From this moment on, air became the compression medium of choice. Purchased in Paris, September 2008.