Abstract: The height of a liquid level from the bottom of a storage tank or the like is accurately determined by using a probe with dual isolated channels to measure the time for an acoustic signal to travel between fixed submerged points and from a transducer in one of the channels to the surface of the liquid. Elapsed time measurements are converted to liquid volume using predetermined velocity-temperature values to compensate for temperature variations in the tank.

Abstract: The burn rate of tobacco is decreased without impairment of its quality of smoking by the application thereto of small amounts of certain salts, preferably hydrated magnesium chloride, which upon heating exhibit a plurality of endothermic reactions at successively increasing temperatures in the range from about 100.degree. C. to about 500.degree. C. In addition, the presence of small amounts of an alkaline material such as calcium hydroxide is desired to counteract marginal changes in the yields of some smoke components and to increase smoke pH.

Abstract: A smoking composition comprising tobacco and a catalytic agent for causing a decrease in the yield of polycyclic aromatic compounds arising from pyrolytic reactions of the composition, the agent being selected from the group consisting of finely divided unsupported metallic palladium or palladium salts which are heat decomposable into metallic palladium.