1. From vital chaos to the gas of chemists
The concept that air is a weighable substance consisting of various gases gained acceptance only in the course of the 18th century. Until then it had been considered one of the four Aristotelian elements and was neither heavy nor light, as long as it remained in its natural place. In his Ortus Medicinae (Amsterdam 1648; Ger. Aufgang der Artzney-Kunst, Sulzbach 1683), the Flemish Paracelsist …