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Originally, gas was only used for lighting for a few hours at the start and end of each day. Storing gas was the solution to make it over a longer period. The first gas holders were a Ã¢â‚¬Å“bellÃ¢â‚¬Â floating in a tank of water. Calibration marks were used to show on the floating bell showed how much gas was being made or used. Later in the 19th century, gas holders became larger and telescopic sections were added. Waterless designs were introduced from Europe in the 20th century. Many gas holders remain in use today in Britain, being filled at night and emptied during the day in the winter. First gas pipes were generally made of iron, they are now made from polyethylene for higher pressures. There are two basic types of gasholder Ã¢â‚¬â€ rigid waterless and telescoping. Rigid waterless gas holders were a very early design which showed no sign of expansion or contraction. There are modern versions of the waterless gas holder, e.g. oil-sealed, grease-sealed and "dry seal" (membrane) types. Telescoping holders fall into two subcategories. The earlier of the telescoping variety were column guided variations and were built in Victorian times. To guide the telescoping walls, or "lifts", they have an external fixed frame, visible at a fixed height at all times. Spiral guided gasholders were built in the UK up until 1983. These have no frame and each lift is guided by the one below, rotating as it goes up as dictated by helical runners. Both telescoping types use the manometric property of water to provide a seal. The whole tank floats in a circular or annular water reservoir, held up by the roughly constant pressure of a varying volume of gas, the pressure determined by the weight of the structure, and the water providing the seal for the gas within the moving walls. Besides storing the gas, the tank's design serves to establish the pressure of the gas system. With telescoping (multiple lift) tanks, the innermost tank has a ~1 ft wide by 2 ft high lip around the outside of the bottom edge, called a cup, which picks up water as it rises above the reservoir water level. This immediately engages a downward lip on the inner rim of the next outer lift, called a grip, and as this grip sinks into the cup, it preserves the water seal as the inner tank continues to rise until the grip grounds on the cup, whereupon further injection of gas will start to raise that lift as well. Holders were built with as many as four or more lifts.