Estimated Date: 1900
Name: Hill and Barnards Sphygmometer
Manufacturer: J.J. Hicks
Description: 6“x 2“x 1.5” red leatherette box with Mnfr inscribed on inside lid. 5.5” long glass tube with glass valve at one end and composition housing at other end holding a rubber membrane which is now quite hard. Calibrated by hand to 250, which is 2.5” or 1 cm therefore 0.25 mm/unit. Has a vial with hard rubber stopper, which is perforated and inner tube to prevent spilling, probably carried mercury.
Reference 1: 33