The New Student's Reference Work/Pressure
Pres′sure, in physics and in engineering the force per unit-area which a fluid exerts upon any surface. To obtain the total force which a fluid impresses upon any given surface we have, therefore, only to multiply the average pressure by the area of this surface. In pure science the unit of pressure is that which exerts a force of one dyne per square centimeter. A larger and often more convenient unit is that adopted by the Paris congress of physicists in 1900, namely, 1,000,000 dynes per square centimeter. This unit practically is exactly represented by the pressure exerted by a column of mercury 75 cm. high at sea level at 0°C. This larger unit is called a barye. One barye=106C. G. S. [centimeter-gram-second] units of pressure.