A method is used for the quantitative measurement of the flow of gas through a pipe, esp. for laboratory purposes, in which the gas passes through a dip-tube immersed below the level of liquid in a vessel, escaping in the form of a regular flow of bubbles of constant volume, which are counted to give a measure of the total flow. The counting is effected acoustically as a function of the noise generated by the bubble flow. The noise produced by each bubble may be picked up by means of an electro-acoustic transducer (11) located above the liquid level (7) and the output signal may be fed to a counter (13).
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