In 1628, English scientist William Harvey observed that when an artery was cut, blood gushed out as if driven by pressure. Blood pressure could be felt by touching the pulse.
In 1835, Julius Erison invented a sphygmomanometer that transmitted the pulse to a narrow column of mercury. As the pulse beat, the mercury would rise and fall accordingly. For the first time, doctors could measure pulse and blood pressure without cutting an artery. However, due to its inconvenience, crude construction, and inaccurate readings, other scientists improved upon it. The sphygmomanometer measures blood pressure based on the height of the mercury column; the barometer measures air pressure in the same way.
In 1860, French scientist Étienne Jules Maret developed what was then the best sphygmomanometer, amplifying the pulse and recording its trajectory on a roll of paper. This portable sphygmomanometer was used by Maret to study abnormal heartbeats.
The blood pressure monitor used by doctors was invented in 1896 by Italian scientist Scipione Rivarocchi. It has an inflatable cuff to block the flow of blood, and doctors listen to the pulse with a stethoscope while reading the blood pressure on a scale.
