Abstract: A method of volumetric measurement of a first closed space of unknown volume which comprises communicating the first space with a second closed space of known volume, changing the known volume of the second space by a predetermined amount, obtaining representations of the pressures in the spaces respectively with the second space at its original known volume and its changed volume, and determining a measure of the unknown volume of the first space from the known volume, the volume change and pressure representations. The method is preferably applied to medical usage for diagnostic purposes with the first space being a body cavity, such as the nasal airway for which a small volume correlates with predisposition to glue ear.

Abstract: A non-cyanide salt composition for use in a fused-salt metal heat treatment bath for carburizing steel contains, as its cations, on the basis of total moles of cations 23 mole % potassium, 41/2% lithium, and the balance substantially sodium, and contains, as its anions, on the basis of total moles of anions 19 mole % chloride and the balance substantially carbonate (precursors of any of these ions counting as the ion). The liquidus temperature of the overall composition is not more than 750.degree. C. The composition further contains 1 to 40 weight % silicon carbide based on the total weight of the anions and cations. A steel component is typically treated with the salt composition at 920.degree. C. for 4 hours.