Notes

Abstract

THE investigation of the properties of radium salts has led to many remarkable results, among which those contributed by MM. P. Curie and A. Laborde to the current number of the Comptes rendus are not the least remarkable. They adduce evidence to show that radium salts give off heat continuously. The experiments were made in two ways. Two small bulbs, one containing 1 gram of a radiferous barium chloride containing about 1/6 of its weight of radium chloride and the other containing a similar weight of ordinary barium chloride, were placed uncler similar thermal conditions with a junction of a thermocouple in each bulb. The bulb containing the radium preparation proved to be 1°.5 hotter than the other, and this temperature difference was maintained. An. independent confirmation was obtained with the Bunsen ice calorimeter. At the moment the radiuni; bulb, was introduced, the mercury, which was previously stationary, commenced to move along the. tube with a, perfectly uniform velocity, and on the bulb being taken out the mercury stopped. From these experiments, which are given as preliminary and. only roughly quantitative the authors conclude that a gram of pure radium would give off a quantity of heat of the order of 100 calories per hour, or 22,500 per gram-atom per hour, a number comparable with the heat of combustion in oxygen of a grarnratom of hydrogen. The disengagement of such a quantity of heat cannot be explained by the assumption of any ordinary chemical, transformation, and this excludes the theory of a continuous/ modification of the atom. The heat evolution can only be explained by supposing that the radium utilises an external energy of unknown nature.