t)n the Nature of certain Bodies. 109 



came ot a deep red brown colour, like phosphorus that has 

 been inflamed and extinguished under water. The gas ex- 

 amined proved to be phosphuretted hydrogen, and in one 

 experiment, continued for some hours, a quantity estimated 

 to be nearly equal to four limes the volume of the phospho- 

 rus employed was given off. The light of the Voltaic spatk 

 in the phosphorus was at first a brilh'ant yellow, but as the 

 colour of the phosphorus changed, it appeared orange. 



I heated three grains of potassium in sixteen cubical 

 inches of phosphuretted hydrogen ; as soon as it was fused, 

 the retort became filled with white fumes, and a reddish 

 substance precipitated upon the sides and upper part of it. 

 The heat was applied for some minutes. No inflammation 

 took place*. When the retort was cool, the absorption was 

 found to be less than a cubical inch. The potassium ex- 

 ternally was of a deep brown colour, internally it was of 

 a dull lead colour. The residual gas had lost its property of 

 spontaneous inflammation, but seemed still to contain a 

 small quantity of phosphorus in solution. ■ 



The phosphuret acted upon over mercury by solution of 

 muriatic acid evolved only one cubical inch and three quar- 

 ters of phosphuretted hydrogen. 



From this experiment, there is great reason to suppose 

 that phosphuretted hydrogen contains a minute proportion of 

 oxyoen, and consequently that phosphorus likewise may 

 contain it ; but the action of potassium on phosphorus itself 

 furnishes perhaps more direct evidences of the circumstance. 

 One grain of potassium and one grain of phosphorus were 

 fused together in a proper apparatus. They combined with 

 the production of the most vivid light and intense ignition. 

 During the process one-tenth of a cubical inch of phosphu- 

 retted hydrogen was evolved. The phosphuret formed, ex- 

 posed to the action of diluted muriatic acid over mercury, 

 produced exactly three-tenths of a cubical inch of phosphu- 

 retted hydrogen. 



In a second experiment, one grain of potassium was fused 

 with three grains of phosphorus ; in this case nearly a quar- 

 ter of a cubical inch of phosphuretted hydrogen was gene- 

 rated during; the ignition. But from the conipound exposed 

 to nuiriatic acid, only one-tenth of a cubical inch could be 

 procured. 



Now it is not easy to refer the deficiency of phosphuretted 



• It i» stated, in the account before referred to of MM. Gay Liissac's and 

 Thenartl'i experiments, that potassiu'.ii inflames in pliospliurcUed hydrogen. 

 My experimentit uptni this pas have been often repvuted. 1 have never pc-r- 

 oeived any luaiiuous ^ippearance; but Ibaveulw^ys operated iu dayli;^ht. 



hydrogen 



