Barometer

Fig. 1: Boyle's experiment "About the greatest height to which Water can be rais'd by Attraction or Sucking Pumps"; Fig. 2: "Wherein is proposed a way of making Barometers, that may be transported even to distant Countries"; Figs. 3 and 4: "Shewing that an Oblique pressure of the Atmosphere may suffice to keep up the Mercury at the wonted height in the Torricellian Experiment, and that the Spring of a little included Air may do the same." Plate 5 from A continuation of New experiments physico-mechanical, touching the spring and weight of the air, and their effects, Part 1, by Robert Boyle (Oxford, 1669).