Meters for Measuring Cold Water

Abstract

In 97 AD. Sextus Julius Frontinus was appointed Commissioner of Water Works of the City of Rome. The high character and intelligence of this official is revealed in his classic treatise De Aquis which is a technical account of the earliest known municipal water supply system. This ancient record of 18 centuries ago shows that Frontinus, like the modern water works official, was faced with the problem of measuring both supply and distribution. However, this old Roman was seriously handicapped because only a meager store of hydraulic knowledge was available. Probably because there was no means of accurately recording seconds or small intervals of time, Frontinus apparently did not grasp the idea of velocity as a function of discharge in the now familiar equation Q = AV, and hence made his comparison of the discharge of pipes and channels on the basis of cross sectional area alone, as if Q were equal to A times some constant. It is small wonder that he was often baffled by the inconsistencies in his computations. However, Hero of Alexandria, the inventor of the steam engine, a contemporary of Frontinus and perhaps his teacher, described the method of measuring the yield of a spring as follows :