Abstract: Disclosed is an apparatus for continually monitoring for the presence of suspended or dissolved gas within a viscous material, such as in the material accumulated in the mud reservoir of a mud system used in an oil or gas drilling operation. Pressurized air is injected into the liquid to agitate and dislodge the gas. The dislodged gas is captured within a sealed chamber upon emerging from the liquid. A sample of the gas is continuously vented from the chamber through an outlet tube under the influence of the pressurized air. A gas sensor is mounted with the outlet tube so as to continually and accurately detect the presence of the gas within the liquid.