74: Scientific Intelligence. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. On Radio-active Barium. — In a preliminary notice Bela v. 

 Lengyel calls attention to the fact that the bodies thus far 

 known which emit Becquerel's rays are of five different kinds, 

 viz., the compounds of uranium, of thorium, polonium, radium, 

 and Debierne's body which is analogous to titanium. Uranium 

 and thorium are well-defined chemical substances, while the three 

 others are merely hypothetical elements. Radium is the best 

 known of these, but from the statements made in regard to it the 

 author believes that it can hardly be regarded as an existing ele- 

 ment. In favor of its existence the two principal facts from a 

 chemical point of view are the higher atomic weight found by 

 Madam Curie for the radio-active barium, and the single foreign 

 line found by Demarcey in the spectrum of such material. In 

 regard to the first point, the author thinks that a body which is 

 present in sufficient amount to raise the atomic weight eight 

 units above barium should not fail to reveal itself in the course 

 of various chemical decompositions. He believes, moreover, that 

 the single spectrum-line noticed by Demarcey does not point to 

 the presence of an element closely analogous to barium, for, as is 

 well known, the spectra of barium, strontium, and calcium con- 

 sist of many sharp lines and less clearly defined bands, similarly 

 grouped in the three cases, and an element almost identical with 

 barium should possess an analogous spectrum. He states also 

 that it should be remembered that these hypothetical elements 

 are always found adhering to other well-known chemical elements. 

 Curie found polonium with bismuth, Giesel found it with lead ; 

 radium is attached to barium, Debierne's element goes with 

 titanium. All these radio-active substances come from pitch- 

 blende, being separated from it by analytical processes. It is 

 difficult to assume that elements exist which differ from others 

 that are well known in nothing except their radio-activity. 



Such considerations as the above led the author to investigate 

 experimentally the question whether radio-active bodies contain 

 new elements or not. He ignited uranium nitrate with two or 

 three per cent of barium nitrate and finally fused the resulting 

 oxides in the electric arc. The mass was dissolved in nitric acid, 

 the solution was evaporated, whereupon a large part of the 

 barium separated as nitrate, then from the decanted liquid a pre- 

 cipitate of barium sulphate was produced which showed radio- 

 activity. The author believes that he has prepared radium 

 synthetically, but does not consider that these preliminary experi- 

 ments are sufficient to decide with certainty whether this is a 

 definite chemical element or not. 



There appears to be a weak point in this supposed synthesis of 

 radium from the possibility that the uranium nitrate used may 



