Dr Davy's Observations on Phosphorus, 51 



phosphorus and camphor exposed to the air on the warm hand, 

 did not shine till rubbed, when it became brilliantly luminous. 

 Phosphorus may also be boiled in and distilled from oil of tur- 

 pentine without inflaming. 



Though phosphorus inflames in pure chlorine gas, its light is 

 extinguished when it is exposed to the vapour of chlorine, as 

 when it is held over an aqueous solution of this substance. The 

 same happens when it is exposed to the vapour of Iodine and 

 Bromine. 



It does not shine in nitrous oxide, though mixed with common 

 air. When heated in this gas it melts, and at the subliming 

 point decomposes the gas explosively with a bright flash. Its 

 light is extinguished by nitrous acid gas or vapour, even when 

 so much diluted with common air as hardly to be perceptible by 

 the sense of smell. 



The vapour of ammonia, of muriatic acid, of distilled vinegar- 

 and of hydrocyanic acid, do not appear to prevent phosphorus 

 from shining ; they rather increase the brightness of its light. 

 It shines in carbonic acid gas, and muriatic acid gas, when the 

 minutest quantity of atmospheric air is present. 



It appears to be soluble, or capable of rising in vapour in 

 muriatic acid gas, carbonic acid gas, and hydrogen gas ; for 

 when these gases perfectly pure have been kept some time over 

 mercury with phosphorus in them, a luminous appearance has 

 been produced (bright flashes of diffused light), when they have 

 been passed alone into a jar of common air. The same eff*ect 

 takes place, when the azote of atmospheric air, deprived of its 

 oxygen by the slow action of phosphorus, is thrown into the at- 

 mosphere, or into oxygen gas. But the reverse is the case, when 

 the oxygen of the atmospheric air has been separated by intense 

 combustion ; however much the phosphorus has been in excess, 

 and though it has been a second time sublimed in the azote, it 

 has not acquired the power of shining on admixture with com- 

 mon air, although from its smell there was no reason to suppose 

 that the gas did not contain phosphorus in solution. 



Mr Graham has pointed out the remarkable effect of diff'erent 

 varieties of carburetted hydrogen in extinguishing the light of 

 phosphorus. The results of my experiments with these gases 

 perfectly agreed with his. I have also found that hydrogen gas 

 obtained from iron-filings and dilute sulphuric acid (the former 



d2 



