7S Scientific Intelligence. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. Properties of Radium. — Giesel has recently announced 

 that vadium gives a pure carmine-red flame-color, which gives a 

 brilliant spectrum. This flame-spectrum is remarkably different 

 from Demarcay's spark-spectrum, since two broad, intense lines 

 occur in the orange-red while the spark-spectrum shows only 

 very faint lines in this region. He has observed also that pure 

 radium bromide, as well as the salt containing barium, gives off 

 bromine continually, while the air in contact with the salt becomes 

 ozonized. This liberation of bromine is accompanied by the 

 appearance of an alkaline reaction (radium hydroxide) and the 

 gradual formation of radium carbonate by the action of atmos- 

 pheric carbon dioxide. When radium bromide thus gradually 

 decomposes, a gas is produced, and the crystals contain a part of 

 it in an occluded condition. Upon dissolving the crystals in 

 water they become milky at first and give off the gas with a 

 crackling sound. A solution of radium bromide behaves simi- 

 larly to the solid substance ; it becomes yellow from free bromine, 

 which remains dissolved, and a colorless gas is constantly evolved. 

 It seemed probable to Giesel that this gas was hydrogen (although 

 oxygen rather than hydrogen would be expected to accompany 

 bromine), but a sample of it when mixed with one-third of its 

 volume of oxygen did not explode when brought into contact 

 with a flame. It is not yet known what this gas is, but a spec- 

 troscopic examination of it is to be made. As would be expected 

 from the investigations of Curie, the gas is exceedingly active, 

 causing phosphorescence and darkening the glass with which it 

 comes in contact. It is suggested that this may be a new gas 

 derived from radium, and that it may be connected with the 

 remarkable inductive action of this substance. It was found 

 that pure anhydrous radium bromide at first phosphoresces with 

 a magnificent bluish light which gives a continuous spectrum. 

 The phosphorescence diminishes after a day or so in consequence 

 of the substance becoming colored, but the activity can be tem- 

 porarily restored by heating and thus decolorizing the salt, 

 although the phosphorescence becomes continually weaker. The 

 pure radium bromide used in the experiments that have been 

 mentioned gives off Becquerel's rays to a marked degree. Pre- 

 viously fused alkali-metal halides are colored by them in a few 

 minutes. — Berichte, xxxv, 3608. h. l. w. 



2. Radio-activity of Uranium. — It was shown some. time ago 

 by Crookes that by simple chemical means uranium could be 

 obtained which was inactive to the photographic film, while the 

 whole of the photographic activity could be concentrated in a 

 small residue, not containing uranium, to which the symbol UrX 

 was given. Fkedekick Soddy has now confirmed Crookes's 



