PHOSPHORUS. 421 



" If the neck of a vessel of this kind hold about one fourth as much 

 as the bulb, by graduating the neck, so that each division will repre- 

 sent a hundredth part of the whole capacity, the result may be known 

 by inspection."* 



(r.) Phosphorus is not luminous in oxygen gas, and does not burn 

 in it even slowly, nor can any light be perceived in the darkest 

 place, till the temperature is raised to 80 or 81, which, if the 

 vessel is small, may be done by warming it by the hands. 



(s.) It then becomes luminous, and is surrounded by white vapors ; 

 this appearance ceases again if the temperature sink to 55 ; at about 

 104 it takes fire in oxygen gas; though not luminous at 55, it ap- 

 pears to be dissolved slowly in the oxygen between that degree and 

 81. 



(t.) If into oxygen gas thus impregnated with phosphorus, nitrogen 

 or hydrogen be thrown up, it becomes luminous. 



(u.) Nitrogen dissolves phosphorus from 55 upward, and it may 

 be distilled in this gas or in hydrogen, and it does not become lu- 

 minous. 



(v.) But a bubble or two of oxygen gas or common air, or any 

 gas mixed with oxygen, renders the nitrogen luminous. 



(w.) More strikingly still if phosphorized nitrogen be let up into 

 such gases ; pure oxygen is however best of all. 



(x.) Phosphorus becomes luminous in common air, whose pres- 

 sure is diminished to one eighth or one tenth that of the atmosphere. 



(y.) Phosphorized nitrogen and phosphorized oxygen, (made by 

 keeping both gases in contact with phosphorus for some hours,) do 

 not become luminous when mixed at 55. 



(z.) Phosphorus is easily dissolved, by simple digestion in oil of 

 olives, almonds, &tc. 



(aa.) Also, in oil of turpentine and other essential oils, but more 

 care is necessary. 



(bb.) Phosphorized oils rubbed on the face and hands,f or poured 

 into hot water, exhibit luminous clouds and flashes. 



(cc.) Phosphorus dissolves in alcohol with a gentle heat, but the 

 experiment is dangerous, as the vial must be corked ; it must there- 

 fore be very strong, and the heat applied very gentle. 



(dd.) A flash of light appears when this spirit is poured upon hot 

 water in the dark. 



4. ELEMENTARY NATURE OF PHOSPHORUS. Sir Humphry Davy, 

 by galvanizing phosphorus in a glass tube, with a battery of 500 pairs 



* For a more precise eudiometer see Dr. Hare's Compendium, p. 170. 

 t It should be ascertained that the phosphorus is all dissolved ; otherwise severe 

 burns may be produced. 



