84 Mr. Graham's Observations on 



4. Certain other gases do not qualify oxygen to act upon 

 phosphorus at low temperatures, in whatever quantity they 

 may be added to it. This is the case with olefiant gas, and 

 with azote obtained by the action of a paste of sulphur and 

 iron on common air. 



The first and third of these facts have been known for a 

 long time ; the second was discovered by M. Bellani de Monza; 

 and the fourth appears to have been first observed by M. 

 Thenard (Traite de Chimie, t. i. p. 236, where the subject is 

 treated at length). 



In experimenting upon this subject, another curious fact was 

 noticed. The presence of a minute quantity of certain gases 

 and vapours entirely prevents the usual action of phosphorus 

 upon the oxygen of common air. Thus the slow combustion 

 of phosphorus does not take place at all, at the temp, of 66°, 

 in mixtures of 



Volumes of air. 



1 volume olefiant gas and . . .450 



1 ditto vapour of sulphuric ether and 150 



1 ditto vapour of naphtha and . 1820 



1 ditto vapour of oil of turpentine and 4444 



A stick of phosphorus was repeatedly left for upwards of 

 24 hours over water in air containing only one-four hundredth 

 part of its bulk of pure olefiant gas, during the hot weather of 

 July and August 1828, thermometer frequently above 70°, 

 without diminishing the bulk of the air in contact. A slight 

 expansion, amounting sometimes to T ^th part, occurred on 

 several occasions. A stick of phosphorus, with a few drops of 

 water, was corked up in a large retort, 213 cubic inches in 

 capacity, and containing common air, with which -^th of its 

 bulk of pure olefiant gas had been mixed. During three 

 months the phosphorus never became luminous, although its 

 surface was gradually covered with a thin white crust. The 

 water present was found to have become slightly acidulous. 



The influence of a minute quantity of ether-vapour, in ex- 

 tinguishing the combustion of phosphorus at low temperatures, 

 may be exhibited in a striking manner. Introduce two or 

 three moist sticks of phosphorus into a pint-stoppered phial, 

 into which, when filled with the white fumes, pour a little ether- 



