xlviii GENERAL SUMMARY OF SCIENTIFIC AND 



chemical plasticity, much superior to that of their elements, 

 and comparable to that of the most active radicals; a curious 

 fact, to be explained by the excess of energy imprisoned in 

 the act of their synthesis. In the act of combination in gen- 

 eral the enenjv of the elements diminishes : but in the for- 

 mation of acetylene, of cyanogen, and of nitrogen dioxide, on 

 the contrary, this energy increases." Berthelot has also suc- 

 ceeded in preparing ammonium nitrite in the solid form. It is 

 a white crystalline mass, tenacious and deliquescent. Heated 

 or percussed, it detonates with violence. Troost and Haute- 

 feuille, in studying the conversion of ordinary into red 

 phosphorus, have shown that two different tensions of phos- 

 phorus vapor exist, one of which corresponds to the ordinary 

 phenomenon of vaporization, the other to that of its trans- 

 formation into the allotropic condition. This latter, which 

 the authors call the tension of transformation, has always 

 a constant value at the same temperature. Ritter has shown 

 that the black variety of phosphorus discovered by Thenard 

 is not a third allotropic modification, but is the result of the 

 presence of some impurity, especially arsenic, as he thinks. 

 Blondlot, on the other hand, could not produce black phos- 

 phorus witli the aid of arsenic, though a trace of mercury 

 gave it very readily. As, however, Thenard's variety, when 

 oxidized, gave no precipitate with hydrogen sulphide, Blond- 

 lot suggests that its color may be due to a mixture of red 

 phosphorus. 



Laspeyres describes some large, well-defined crystals of 

 metallic antimony some of which were eight millime- 

 ters on a face obtained from a cavity in the slag of a met- 

 allurgical establishment using antimonious lead ores. The 

 terminal interfacial angles of the rhombohedrons were 87 

 H' to 87 13', the lateral 92 52'. These were mixed with 

 some very curious twin crystals. Apjohn has discovered the 

 presence of vanadium in a meteoric stone which fell at Adare, 

 Ireland, in 1810, and which is now in the Mineralogical Mu- 

 seum of Trinity College, Dublin. Gernez obtains octahedral 

 borax from strongly sursaturated solutions, whether these 

 be obtained by ebullition or by spontaneous evaporation in 

 the cold. But if the solution be touched with a crystal of 

 prismatic borax, the excess of borax crystallizes in prisms. 

 Both forms then can be obtained at the same temperature; 



