308 Scientific Intelligence. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. Atomic Weight of Beryllium. — A series of very careful 

 determinations of this atomic weight has been made by C. L. 

 Parsons of New Hampshire College. Two organic compounds 

 of beryllium, the acetylacetonate, Be(C 5 H 7 2 ) 2 , and the basic 

 acetate, Be 4 0(C 2 H 3 2 ) 6 , were used in this work, both of which 

 are easily purified, since they can be readily crystallized from 

 various solvents, and since they possess the additional remarkable 

 property of subliming unchanged. The compounds, after being- 

 weighed, were treated with nitric acid in platinum crucibles, and 

 after evaporation the residues were ignited and the resulting 

 beryllium oxide was weighed. Seven determinations by means 

 of the acetylacetonate gave an average result of 9-113 for the 

 atomic weight (where O = J 6, H = 1*008, C = 12*01), while nine 

 determinations with the basic acetate gave exactly the same 

 average. The maximum and minimum results were 9*142 and 

 9*081. The results agree very closely with the atomic weight 9*1 

 adopted in the "International" table. — Jour. Amer. C/iem. Soc. r 

 xxvi, 721. h. l. w. 



2. Connection between the "Volatility of Compounds and the 

 Forces at Play within the Molecule. — The view has been brought 

 forward by Geoffrey Martin that chemicall} 7 unstable com- 

 pounds are, as a class, characterized by their volatility and 

 fusibility ; chemically stable compounds by their involatility and 

 infusibility. For example, SiCl 4 , BCL, AlCl a , SnCl 4 , etc., are all 

 volatile and also easy to decompose, while the corresponding 

 oxides are far less volatile and less easily decomposed. It is 

 pointed out, further, that high valency compounds are usually 

 more volatile than the corresponding compounds of lower valency; 

 for instance, SbC) 5 is more volatile than SbCl 3 . This behavior is 

 regarded as due to the greater intensity of chemical forces in the 

 lower valency compounds, as compared with the others. It 

 seems, therefore, that it is the internal chemical forces which the 

 atoms exert on each other in the molecule which decide the 

 external attractive force with which the molecules themselves are 

 attracted together, and, therefore, the volatility of the compound. 

 The author believes that the chemical forces within the molecule 

 determine also the solubility, fusibility, hardness, etc., of com- 

 pounds, and that if these forces were known it might be possible 

 to calculate mathematically the physical properties of chemical 

 compounds. — Chem. JVeios, lxxxix, 241. h. l. w. 



3. Method for the Deter mi?iat ion of Chloric Acid. — This 

 determination is usually carried out by reducing the chlorate to 

 chloride and determining the latter by Yolhard's volumetric 

 method. The reducing agents heretofore used have been various 

 ones, such as zinc in some form, ferrous sulphate, etc. Hendrix- 



