100 YEARS AGO

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. ... 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 under 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 radium 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. ... 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 gram-atom 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.

From Nature 26 March 1903.

50 YEARS AGO

The Cecil Peace Prize of the Association of Universities of the British Commonwealth has been awarded for 1952 to K. H. Dawson, of the London School of Economics (at present at the Graduate School, Princeton University). The subject for the competition for 1953 is “Has the United Nations Organization been successful in carrying out the objects for which it was formed as defined in the Preamble and Chapter 1 of the Charter? Do you recommend any, and if so, what amendments in the terms of the Charter?” Essays must be sent before November 1 to the Secretary, Association of Universities of the British Commonwealth, 5 Gordon Square, London, W.C.1, from whom further details can be obtained.

From Nature 28 March 1953.