The measuring principle of the present viscometer is based on the correct theory of the previously reported capillary viscometer for gases. The viscometer, here reported, has a very simple construction and enables us to measure easily the viscosities of gases in a short time (a few minutes), without the necessity of measuring the flow rate. Results of experiments show that the viscosities measured by the present viscometer are in good accordance with those obtained by Sutherland's equation for the viscosity of gases.
