Sphygmomanometer (blood presure apparatus), 1897-1910.
© Science Museum / Science & Society Picture Library
This apparatus was devised by Leonard Hill (1866-1952) and Harold Barnard, and was produced by J Hicks, London. A rubber cuff was inflated above the elbow to obstruct the pulse, and the manometer needle ceased to vibrate when the pulse disappeared. Sphygmomanometers were invented in the 19th century, but were not commonly used until the 1920s.