Polonium and Radio-Tellurium

Abstract

SINCE the discovery of polonium—the first radio-active substance investigated by Madame Curie—much doubt has existed as to its true nature and as to its relationship with radio-tellurium, subsequently separated by Prof. Marckwald from radio-active bismuth salts. Several papers which have recently been published throw considerable light on the problem, without, however, giving to it a definite solution. Madame Curie (Phyikalische Zeitschrift, No. 5) has determined the constant of decay characterising her “polonium,” and finds that it is practically identical with that ascribed by Prof. Marckwald to his radio-tellurium; in both cases the activity falls to half its value in about 140 days, so that there can be little doubt that the two substances are identical. In discussing the chemical properties of “polonium,” Madame Curie concludes that there is no ground for considering that it more closely resembles tellurium than bismuth. In No. 4 of the Berichte of the German Chemical Society, Prof. F. Giesel has investigated the radio-activity of a “β-polonium” which differs from the older polorium or radio-tellurium by its emitting β rays instead of α rays; the activity of this substance falls to half its value in 6.14 days. This value does not correspond with the rate of decay of any of the known degradation products of radium. Meyer and von Schweidler, on the other hand (Proceedings of the Vienna Academy of Sciences, February 1), have obtained a radio-active bismuth which appears to behave as a mixture of radium D, radium E, and radium F; but Madame Curie (Physikalische Zeitschrift, No. 6), in discussing this result, considers that polonium cannot be identical with radium D or radium E, but only with radium F. Closely connected with these researches must be mentioned an investigation by Prof. H. Becquerel (Physikalische Zeitschrift, No. 6) of some of the characters of the α rays emitted by radium, and by substances rendered active by radium.