Chemistry and Physics. 75 



SCIENTIFIC INTELLIGENCE, 



I. Chemistry and Physics. 



1. The Preparation of Metallic Radium. — The successful pre- 

 paration by Mme, Curie of a small quantity of this metal was 

 noticed in the last number of this Journal, but, nevertheless, the 

 preparation of barium-radium metal by a different method appears 

 to be worthy of mention. E. Ebler considered the preparation 

 of the metal an important matter, as he conceived the possibility 

 that radium might not be an element at all, but a comparatively 

 stable radical, possibly a radical containing helium, and that the 

 salts of this radical resemble barium salts in the same way that 

 ammonium salts resemble those of potassium. It was his view 

 also that the preparation of radium amalgam, which had been 

 effected by Coehn, did not contradict this radical theory on 

 account of the well-known formation of ammonium amalgam. 

 Ebler's method of preparing the metal was by slowly heating the 

 mixed barium and radium azides, Ba(N 3 ) 2 and Ra(N 3 ) 2 , since it 

 had been shown by Curtius and Rissom that the metals calcium, 

 strontium and barium may thus be produced from their azides. 

 The method appears to be preferable to that used by Mme. Curie, 

 as the azide is stable and, as Ebler has shown, it does not appear 

 to be decomposed by the radium radioactivity. Ebler found that 

 the mixture of metals produced in this way gave the same y radia- 

 tion as the original salt, and he concludes that metallic radium is 

 capable of existence, and is analogous to metallic barium. — 

 Rerichte, xliii, 2613. h. l. w. 



2. The Reduction of Oxide of Iron by Solid Carbon. — 

 Charpy and Bonnerot have studied the interesting question 

 concerning the action of the solids under consideration in the 

 absence of gases, They employed carefully purified ferric oxide 

 and graphide which had been heated separately to 1000°. The 

 materials were then finely pulverized and mixed in an agate mor- 

 tar, and the mixture was agglomerated at a pressure of several 

 thousand atmospheres. Since it appeared to be impossible to heat 

 the mixture in the absence of every trace of gas, even by the use 

 of a mercury pump, the matter was studied by observing the 

 rapidity of the reaction, measured by the amount of gas given off, 

 at varying, very low pressures. As an example, a series of ex- 

 periments carried on at 950° C. gave the following results : 



Pressure in Volume of gas 



millimeters given off per 



of mercury hour, com. 



0-01 0-10 



0-1 0-14 



1- 0-31 



2- 0-56 



4' 0-80 



8- A 1-07 



