442 PHOSPHURETS. 



(h.) Water absorbs a portion of this gas, by agitation ; if thorough- 

 ly deprived of air at 55, it absorbs j- of its bulk, (Dalton ;) ^ 

 (Thomson.) 



(i.) Heat, below boiling, expels it unaltered and inflammable. 



(j.) Spontaneously decomposed by exposure to the air; oxide 

 of phosphorus is precipitated, and the gas rises uninflammable, (spon- 

 taneously.) 



(&.) Solution of this gas does not change the test colors. This 

 gas being readily absorbed by sulphate of copper, and chloride of 

 lime, a sure method is thus afforded of ascertaining whether it is con- 

 taminated with common hydrogen. 



SI.) Precipitates many metallic solutions in the state of phosphuret. 

 m.) Potassium does not inflame in phosphuretted hydrogen gas, 

 even when heated, but the potassium is converted into a phosphuret, 

 and 2 measures of the gas become 3. 



(n.) Decomposed by heat, by electricity, and by vaporizing sul- 

 phur through this gas; it then becomes sulphuretted hydrogen.* 

 Phosphuretted hydrogen collected in a jar with a cap and stop 

 cock, blazes when the jar is depressed into the water and the orifice 

 opened ; or if a bent tube be attached to the cap, and the bubbles 

 be allowed to issue from beneath the water, they flash as they break 

 into the air.f 



OTHER VARIETIES OF PHOSPHURETTED HYDROGEN. 



1. Sub-phosphuretted hydrogen gas. 



(a.) This is the gas, already named, which remains after the com- 

 mon phosphuretted hydrogen has deposited J of its phosphorus,^, and 

 has thus lost its spontaneous inflammability ; it is called at present, 

 gub-phosphuretted hydrogen, and by some proto-phosphuretted hy- 

 drogen. 



(b.) For perfect combustion it requires 1.25 volumes of oxygen; 

 ,75 saturates the phosphorus, and .50 the hydrogen ; as the vapor of 

 phosphorus requires its own volume of oxygen, this gas is inferred 

 to consist of 1 vol. of hydrogen, 0.0694 + 0.75 of a vol. of phosphorus, 

 0,6250 = .(5944, 



* We are not informed what becomes pf the phosphorus ; whether it is precipitated 

 or remains suspended in vapor. 



t It is supposed that many of these fires which are said to be seen at night, around 

 burying grounds, and other place? where animal and vegetable substances are un- 

 dergoing decomposition, arise in part at least, from phosphuretted hydrogen. Trav- 

 elling once, through a deep valley, in a dark night, between Wallingford and 

 Durham, Conn. I was surrounded by multitudes of pale lambent lights; they were 

 every moment changing their position, and some of them were within the reach of 

 my whip ; they were yellowish and not intense. 



I Thomson. Dumas says one third, 



