Connection to other instruments

Within the instruments that Hall brought back from Europe, the air pump resembles the impact that the special gravity beads had in the bigger picture of understanding nature. Hall supposedly used these beads in a lesson on hydraulics where he was able to demonstrate density of different liquids. Each bead was put into a particular liquid to see if it was neutrally buoyant (neither sinking or floating), which would mean that the density of that particular liquid was equal to the density of that specific bead. In the same way that the air pump was able to reveal the complicated features of air, the bead was able to reveal liquid's complicated feature: that each liquid was unique with density being a key part in identifying its uniqueness. With air (gas) and liquid being two of the three phases of matter, these two instruments were complements in providing an incentive to gain advanced knowledge of substances that are foundations of our world.