The instrument would be calibrated against a manometer, which would be the calibration standard. The word "sphygmomanometer" (, ) uses the combining form of "sphygmo-" + "manometer". This pressure can easily be measured with a manometer. The measurement of pressures within the rectum and anus with a manometer (pressure-sensing probe). A manometer uses the weight of the liquid to indicate air pressure. The Penning manometer (vacuum gauge) emerged as a practical application. The design of a McLeod gauge is somewhat similar to that of a mercury-column manometer. The hydrogen was inserted by squeezing the balloon while monitoring the pressure on a manometer. Represented by centimeters of water pressure (cmH2O) and measured with a manometer. The pressure drop across the bed is measured by a similar manometer. In 1906 Christian Saugman improved the device by adding a water manometer for measurement purposes. Using his Warburg manometer, he mixed a slice of liver with purified ornithine and citrulline. Usually the snow pillow will be connected to a manometer. Using the manometer he tested those hypotheses one by one.