﻿506 Dr. T. Ewan on the Rate of Oxidation 



According to Thorpe and Tutton* phosphorous oxide, P 4 6 , 

 shows phenomena in presence of oxygen gas which possess 

 the strongest resemblance to those exhibited by phosphorus 

 itself. They suggest that the more rapid reaction at lower 

 pressures is due to the increased volatility of the phosphorous 

 oxide. 



Joubertf noticed similar behaviour with sulphur and 

 arsenic. 



Friedel and Ladenburg % found that a mixture of silicon 

 hydride, SiH 4 , and oxygen inflames spontaneously on de- 

 creasing its pressure, and Houton de Labillardiere § had 

 previously made a similar observation with phosphine (PH 3 ). 



Van de Stadt || mentions that nickel carbonyl, Ni(CO) 4 , 

 appears also to behave similarly. Reicher and Jorissenlf 

 found, however, that it is still spontaneously inflammable in 

 oxygen under a pressure of 13 atmospheres. 



Engelmann ** found that certain Bacteria show a preference 

 for a certain definite concentration of dissolved oxygen. 

 Greater or smaller concentrations seem to be less favourable 

 to their existence. 



Labillardiere's observation with phosphine was repeated by 

 van'tHoflftt? w ho found that at ordinary temperatures the 

 spontaneous inflammation of the mixture took place when 

 the partial pressure of the oxygen was about -^ atmosphere. 

 The gases were preserved over a saturated solution of calcium 

 chloride. When the partial pressure of the oxygen was 

 higher or lower than ^ atmosphere, only a slow combination 

 took place. 



H. J. van de Stadt J J in 1893 investigated the subject 

 more fully in order to find how the velocity of the slow 

 combustion which precedes the explosion changes with the 

 concentration. He found that the reaction proceeded slowly 

 and with a nearly constant velocity, which showed no notice- 

 able acceleration until the explosion-pressure was reached, 

 when the explosion took place, sometimes at once, sometimes 

 on standing. 



This reaction was therefore not a very suitable one for the 



* Journ. Chem. Soc. 1890, p. 569. 



t Theses presentees a la Faculte des Sciences de Paris, 1874. 



% Ann. Ch. Phys. [4] xxiii. p. 430 (1871). 



§ Ann. Ch. Phys. \i p. 304 (1817). 



|| Zeit. Phys. Chem. 1893, xii. p. 322. 



5] Maandblad voor Natuurwetenschappen, No. 1 (1894). 

 ** Botanische Zeitung, 1882, p. 320. 

 tf Etudes de Dynamique Chimique, p. 60 (1884). 

 XX Zeit. Phys. Chem. 1893, xii. p. 322. 



