This spacecraft-like structure is in fact a 'gas holder'. A gas holder (sometimes also called a 'gasometer') is a large storage tank. Natural gas or town gas is stored in it under near atmospheric pressure and at ambient temperature. In the first half of the twentieth century, such a gas holder was a common structure. Gas holders were typically cylindrical in shape and made of iron. The volume of the tank can be adjusted to the amount of gas stored in the tank.

After the introduction of natural gas, the use of gas holders fell into disuse, and they were usually only used to balance the pressure of the gas in pipelines. The pressure is regulated and maintained by a container that can move up and down telescopically. Inside the tank, the gas is 'sealed' by a system of communicating vessels, resting in a water tank, in which the water acts as a 'seal' so that the gas present cannot escape.