An instrument that measured altitudes via the boiling point of water
A thermobarometer in a volumeter is used to measure both temperature and pressure, which are important factors in determining the volume of a substance. By taking into account temperature and pressure, the volumeter can accurately calculate the volume of the substance being measured.
The tube that contains only glass beads is called the control tube. It is used as a control in the germinating seed experiment to provide a baseline comparison for the experimental tube with seeds.