464 Scientific Intelligence. 



neutralized with ammonia to the point of turbidity." If they 

 always did this in applying the oxalic acid test, there is every 

 reason to suppose that their new oxide is largely thoria, for they 

 precipitated in the presence of ammonium oxalate in separating 

 from the earths of the cerium and yttrium groups, and thorium 

 oxalate is well known to be soluble in ammonium salts. There 

 is a marked resemblance to thoria in the description of the prop- 

 erties and reactions of the earth, but it is evidently not pure 

 thoria, for the equivalent found, 44*4, is much too low for that 

 oxide. To the substance the name "Euxenerde" is given, which 

 would probably correspond to euxenium for the metal. It may 

 be mentioned that these authors have found another unknown 

 substance in euxenite, which they think may be related to tanta- 

 lum, but has a more marked basic character. — Berichte, xxxiii, 

 1064. h. l. w. 



3. The Action of Radium Rays upon Selenium. — Eugexe 

 Bloch has recently described some experiments upon the effect 

 of the rays emitted from radio-active barium carbonate upon the 

 electric conductivity of selenium. It has long been known that 

 the action of light diminishes the resistance of this element, and 

 it has been shown also that the Rontgen rays have a similar 

 action. The experiments under consideration now show that 

 Becquerel's rays produce the same effect, but apparently to a 

 slighter degree. The investigation was made with a sample of 

 barium carbonate which possessed an activity about 1000 times 

 that of ordinary uranium. — C. R., cxxii, 914. h. l. w. 



4. The Reducing -power of Magnesium and Aluminum. — A 

 number of striking experiments, based upon the affinity of these 

 metals for oxygen, are described by A. Duboin. One of these 

 which seems to be novel, although extremely simple, consists in 

 placing moistened magnesium or aluminum powder upon a scori- 

 fier or porous plate, covering the mixture with dry magnesium 

 and igniting. As soon as the combustion reaches the moistened 

 part an exceedingly brilliant flame appears, which is due to the 

 reaction of magnesium with water-vapor. The magnesia that is 

 lormed is left in long filaments. Another interesting experiment 

 is the action of aluminum upon alumina. Four atoms of the 

 metal to one molecule of the oxide are mixed, and upon ignition 

 they react with vivid incandescence, forming, it is stated, the 

 oxide A1 2 0. — C. R. y cxxxii, 826. h. l. w. 



5. A Method of Determining Atomic Weights, Based upon 

 the Transparency of Substances to the J£-Rays. — Soon after the 

 discovery of the Rontgen rays it was recognized that the trans- 

 parency of substances to them depended upon the atomic weights 

 of the elements contained in the substances. L. Benoist, who 

 has made a study of this matter, has now applied this behavior 

 to the determination of the atomic weight of indium. If this 

 metal is bivalent its atomic weight is 75 '6, but if trivalent it is 

 113 # 4. The higher valency is the more probable one. Using an 

 organic compound of indium and the metal itself, Benoist has 



