The gasioaded type operates in accordance with Boyle’s law of gases, which states that for a constant temperature process, the pressure of a gas varies inversely with its volume. Thus, for example. The gas volume of the accumulator would de cut in half if the pressure were doubled. The compressibility of gases accounts for the storage of potential energy. This energy forces the oil out of the accumulator when the gas expands due to the reduction of system pressure when, for example, an actuator rapidly moves a load. Nitrogen is the gas used in accumulators because (unlike air) it contains no moisture. In addition, nitrogen is an inert gas and thus will not support combustion. The sizing of gas-laded accumulators for given applications is covered in Chapter 14, after Boyle’s law of gases is discussed.