Abstract: A device for measuring the concentration changes of a vapor at various moisture contents ranging from saturation to dry and under different confining stress as it diffuses through a porous media which includes a porous central housing having a central space and a fluid conveying line extending into the central space of the central housing and an outer housing which encompasses for containment of the central housing and is positioned in an outward spaced relation from the central housing to form a medial space, between the external housing and the internal housing and having a second fluid conveying line extending into the medial space.

Abstract: A high resolution thermometer operated by the pressure of a solid/liquid se mixture is characterized by a vessel containing the mixture, a pressure sensor and a pressure indicator. A relatively small change in the temperature to be measured causes the proportion of solid and liquid in the vessel to change, thereby producing a dramatic change in pressure which can be measured with greater accuracy than the relatively small temperature change. Temperature is determined by converting the pressure to temperature using the appropriate thermodynamic relationship.