PHOSPHORUS. 419 



(c.) Crystallizes by melting it under water, and when the crust 

 has congealed, it must be pierced, and the liquid interior poured out, 

 by inclining the vessel ; the crystals are needles, or, if the cooling 

 has been slow, octahedra.* 



(d.) Crystallizes also from solution in an essential oil, by slow 

 evaporation, and in dodecahedra, from solution of phosphuret of sul- 

 phur. 



( e.) Becomes covered with a brownish crust, by keeping. 



(/.) Melts at 99, and this must be done always under water 

 Volatilized at 219, boils in close vessels at 554, takes fire in the 

 air, at 148.f 



(g.) Highly inflammable, and burns with a bright white flame, and 

 much white smoke, which if collected is found to be acid. 



(A.) It burns with intense splendor in oxygen gas, but the facts on 

 this head are reserved for phosphoric acid. It burns also in chlo- 

 rine and other gases, to be mentioned in their proper places. f 



(i.) Burns slowly without flame ; in the dark, with a beautiful 

 blue luminous cloud, and with a white smoke in the light ; but not 

 in air artificially dried ; these appearances are more distinct, in pro- 

 portion as the temperature is higher, and a garlic smell accompanies 

 them. Mr. Boyle found that 3 grains emitted light for 15 days. 



(/.) A stick of phosphorus, placed in a glass tube, for a handle, 

 will leave luminous traces, if drawn on a wall in a dark room, but it 

 does not show well unless in a warm place ; in the cold, it is not ap- 

 parent. 



(k.) Jl piece of phosphorus, between two folds of paper, is easily in- 

 flamed by friction. 



(I.) By means of a little tallow or wax, stick some phosphorus 

 to the side of a wine glass, or tumbler, and it may be inflamed by mix- 

 ing sulphuric acid and water, in the vessel. 



(m.) Phosphorus merely luminous does not burn the fingers, still it 

 is best always to take hold of it with forceps. 



(n.) Phosphoric fire bottles are formed by putting very dry phos- 

 phorus into a dry vial with a small mouth, and then introducing a hot 

 iron rod and rolling the vial upon it as an axis ; it must be corked as 

 soon as the iron is withdrawn. 



* By melting and cooling large quantities under water, it has been obtained in oc- 

 tahedral crystals of the size of cherry stones. 



t According to Higgins, if quite dry it takes fire at 60. most authors say 108, 

 or 109. 



t Mr. Graham has observed that its combustion is prevented by the presence of 

 very small quantities of foreign gases and vapors, as l-450th defiant, l-150th etherial 

 vapor, l-1820th vapor of naptha, l-4444th of that of oil of turpentine, &c. Turner. 



