The invention relates to a method for automatically monitoring the liquid content in a gas, and in particular the gas leaving a scrubber and entering a compressor. In the method, a sample of fluid is taken from the outlet of the compressor, its temperature and pressure are automatically varied, and the pressure and temperature at which condensation forms is automatically detected. The pressure and temperature thus detected can be used to determine the liquid content in the gas. In a variant method, the temperature and pressure of the sample are automatically varied, and the rate of liquid condensation is measured to determine the liquid content. The invention also extends to a device for cooling a gas so that the liquid content of the gas can be determined, including a cooled housing with a cavity therein, and means for measuring the temperature and pressure within the cavity.