(Chemistry)a graduated glass tube in which mixtures of gases can be made to react by an electric spark, used to measure changes in volume of gases during chemical reactions (化)空气纯度测定仪
late 18th cent. (denoting an instrument used to measure amounts of oxygen, thought to be greater in fine weather): from Greek eudios 'clear, fine' (weather), from eu 'well' + dios 'heavenly'