Concerning the Weight of Air

Abstract

We perceive the weight of air in two ways; it can either be weighed collectively or in parts. We term the collective weight of air the pressure it exerts in a perpendicular direction as in a cylinder. For example, a person can imagine to himself a perpendicular cylinder of air (even when its height is not specifically determined), the base of which in its circumference or roundness, if you will, is similar to that of an groschen, a gulden, or an imperial thaler, or to that of a man’s head or the brim of a hat. I say that the weight of a cylinder of air, whose circumference or roundness is that of a groschen is the same as that of water in a tube (which is like a groschen in roundness) 19 Magdeburg cubits high. This is to say that the weight of air presses down as much as the weight of water 19 Magdeburg cubits high. And again I repeat: the weight of a cylinder of air whose diameter is that of a Rheinish gulden is the same as the weight of water in a tube of a like diameter 19 cubits high. And so it continues proportionately, as will be seen in the following Chapter.