A ‘Heath-Robinson-like’ device invented by Dudgeon in 1882 which records and measures the heart rate by transmitting movement from the radial pulse onto a paper trace.
A sensitive manometer sits on the radial artery and the resulting tiny movements are amplified through to a needle by means of a weighted pulley. A clockwork mechanism turns a roller which winds recording paper under the needle to record a trace. The instrument is unsigned. The mechanism and lined case are in mint condition and perfect working order and from appearances may never have been used. This is one of the cleanest examples I have seen and may date to the early 20th century although they were of the moment in the late 1800s.