Abstract: A cryostatic system utilizing a liquefied gas in which an object or substance to be cooled in a thermostatic chamber without a stirrer and electric heater therein is cooled initially by a liquid coolant at a cryogenic temperature for rapidly lowring its temperature to an intended level and, upon reaching the proximity of said intended level, a temperature sensor detecting the same actuates a temperature controller controlling a heat exchanger, which when actuated gasifies the liquid coolant and controls the temperature of the thus gasified coolant. Thus, upon reaching the proximity of said intended level, said object or substance is cooled by the gasified coolant to be thermostatically controlled thereto with a minimized coolant consumption.

Abstract: In a liquid level indicator for an extremely low temperature-liquefied gas wherein a current is caused to flow through a superconductor wire immersed in the extremely low temperature-liquefied gas, a voltage across terminals of the superconductor wire is measured, and the liquid level of the liquefied gas lying between the terminals is gauged on the basis of the measured value, the improvement therein comprising the providing of a current supply portion which, at first, increases the current to be fed to the superconductor wire up to the so-called plateau region in a current - voltage hysteresis curve of the superconductor wire, and thereafter, decreases it down to a return-path rectilinear region in the curve departing from the plateau region, the liquid level being gauged on the basis of the measured value of the terminal voltage of the superconductor wire as obtained by the use of the decreased current.