A bridge viscometer for measuring specific viscosity, .eta..sub.sp(t), includes four capillaries, a delay volume, and a pressure transducer. The pressure transducer generates a signal indicative of a pressure differential, .DELTA.p(t), as a sample is introduced into the bridge viscometer. The specific viscosity, .eta..sub.sp(t), of the sample is calculated based on the pressure differential, .DELTA.p(t), and a predetermined internal pressure, IP.sub.0.