Abstract: A container assembly is disclosed which incorporates a chemical indicator normally hermetically sealed from the ambient atmosphere, but exposed to the atmosphere upon opening of the container assembly. The indicator is adapted for changing appearance, either color or granule or crystal form, upon exposure to moisture or oxygen. The indicator is either located in the interior of a hermetically sealed container, or is sealed in a frangible envelope which is operatively associated with a closure member of the container and is ruptured upon opening, or attempted opening of the container.

Abstract: An improved system for detecting the location of a molten metal/slag interface during the casting of electroslag remelted hollows is provided. The system includes a gamma ray radiation source (30) and a scintillation counter (40). The source (30) and counter (40) reside outside the casting crucible (1) and are held in fixed spatial relationships with respect to one another and with respect to the mandrel (10). The radiation from the source (30) is directed through the crucible (1) and through the annular casting zone (9) defined between the sidewalls of the upwardly driven mandrel (10) and the crucible (1). The counter (40) provides an electrical signal responsive to the rate of radiation events detected thereby.