110 Scientific Intelligence. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. The Behavior of the Radio-Elements in Precipitation Reac- 

 tions. — Fajans and Beer have discussed this matter in connec- 

 tion with some investigations of their own. The conclusion has 

 been reached by recent researches that the radio-elements fall 

 into groups or pleiads, usually accompanying an ordinary element 

 which may be called the chief element. According to all expe- 

 rience the radio-elements of such a group are not separable by 

 chemical means from the chief element, and their proportions 

 remain unchanged when this element is subjected to fractiona- 

 tion. For instance, there is a group corresponding to lead, 

 another to thorium, another to tellurium, and so on. 



The authors consider particularly the precipitations of radio- 

 elements in cases where the chief element is absent. If they are 

 chemically identical with the chief element, they should be pre- 

 cipitated along with any common element by means of any 

 reagent which would also precipitate the chief element in case it 

 were present, and this appears to be their behavior. For 

 instance, radium E, which goes with bismuth, is precipitated 

 almost quantitatively (when bismuth is absent) along with barium 

 carbonate, lead sulphide, copper sulphide, cerium hydroxide, 

 barium sulphate in very weakly acid solution, and by metallic 

 tellurium formed by the action of stannous chloride in weak 

 acid solution, but it is not precipitated with barium sulphate in 

 strongly acid solution, nor with lead sulphate, nor with metallic 

 arsenic precipitated by stannous chloride. Since bismuth, if pres- 

 ent in weighable quantity, would behave in the same way, it 

 appears that the radium E, although it was present at the very 

 great dilu- tion of about 10 -12 moles per liter, followed precisely 

 the bismuth reactions. 



The authors discuss the matter much further and conclude that 

 previously assumed adsorption phenomena have little to do with 

 the precipitation of the radio-elements. They believe also that 

 the chemical character of such radio-elements as are not identical 

 with any common element may be shown by their behavior in 

 precipitations. — Berichte, xliv, 3486. h. l. w. 



2. A New Source of Gallium. — This metal, which was discovered 

 by Lecoq de Boisbaudran in 1875 in zinc blende, has been detected 

 spectroscopically in various rocks and mineral waters since the time 

 of its discovery, but there has been no material found which would 

 furnish a convenient supply of this very rare element. It required 

 4300 kg. of blende to furnish 63 g. of the metal at the time of Bois- 

 baudran's investigations, a yield of only about 0*0015 per cent. 

 Bardel and Boulanger have now detected gallium in samples 

 of commercial aluminium, 'and the spectroscopic indications of its 

 presence were so strong that they undertook its extraction from 



