What device can be connected to a water column?

A water column is a device used to measure the level of liquid within a tank or a pressure in a system through the height of water. It is specifically designed to work with hydrostatic pressure, making it essential for certain applications in engineering and fluid dynamics.

When examining the choices, the steam gauge is the most appropriate answer because it is often utilized in conjunction with a water column to indicate pressure changes caused by steam within a vessel or system. It can be directly connected to a water column to effectively measure and display the pressures that might arise from steam, which can be crucial for monitoring and maintaining appropriate operational conditions in systems involving steam.

The other options, while they may relate to water systems, do not directly connect or operate with a water column in a manner that provides pressure readings. A water heater and an electric heating element are more focused on managing water temperature rather than measuring pressure. The boiler feed pump is designed to transport water to a boiler but does not interface with a water column specifically for pressure measurement.