Abstract: A method is disclosed for substantially eliminating undercooling in a liquid cooled below its freezing point which comprises utilizing a nucleating agent system comprising:(1) a nucleating agent which is a metal compound, insoluble in the liquid, the metal compound and liquid having similar molecular space groupings; and(2) at least 0.075 wt. % based on the metal compound of a soluble salt of a metal which is the same metal as that of the metal compound.In a preferred embodiment the valence state of the metal of the salt is the same as that of the metal of the metal compound. In another embodiment a metal compound of limited solubility, e.g., less than 1% by weight in the liquid, more preferably about 0.15 to about 0.25 wt. %, is utilized to serve the function of both the insoluble nucleating agent and the soluble metal salt.Where the liquid is water, deuterium oxide or mixtures thereof the preferred metal compound is cupric sulfide and the preferred salt is cupric sulfate.

Abstract: A temperature measuring device useful for measuring the temperature of urine samples is disclosed comprising a solid solution having incorporated therein a nucleating agent and an indicating dye system. The preferred solid solution is a mixture of ortho-chloronitrobenzene and ortho-bromonitrobenzene. The preferred dye systems are pinacyanol iodide and a mixture of bromcresol purple and ethyl red. A novel aspect of the thermometer is that it is adapted to indicate a predetermined temperature at an observable initiation of melt temperature which is about 0.3.degree. to about 1.9.degree. F. below the completion of melt temperature of the composition. The thermometer is a real time device.