ON MeTALLIC PHOSPHURETS. Ont 



times growing darker, at others becoming singularly white. 

 To avoid the latter accident, which is owing to the volati- 

 lization and combustion of the phosphorus, it should be 

 washed and dried cold. It then retains its brown red tint, 

 and has the following properties. 1. Rubbed between the 

 fingers it yields a smell of garlic. 2. Thrown on a hot iron, 

 it emits the same smell, accompanied with a very beautiful 

 phosphorescence, and leaving a residuum of phosphate of 

 lead, fusible before the blowpipe, mixed with some white 

 oxide. 3. Adds expel from it no aeriform bubbles, but de. 

 velope a nauseating and unequivocal smell of phosphuretted 

 kidrogen. 4. Nitric acid dissolves the greater part of it, 

 but without the least extrication of nitrous gas; and the re- 

 siduum is nothing but phosphorus. 



From all these" properties I conclude, that this substance Its nature. 

 is composed of oxide of lead, phosphorus, and a little hi- 

 drogen ; or that it is a hidroguretted phosphuret of oxide 

 of lead*. 



§ 6. Water, alkalis, and spirit of wine in which phos- Nitromuriate of 

 phorus has been digested precipitate the nitromuriate of ^"^''"^"y P"^^- 

 antimony white; but alcohol impregnated with phosphuret ""^'^^''''^ 

 of potash occasions in it a fine brown precipitate, which, 

 being washed and dried without heat, remains unaltered 

 and has a considerable resemblance to kermes mineral. The 

 mode in which this powder is formed; its phosphorescence 

 by the action of caloric; its quiet and partial solution ia 

 muriatic acid, which produces with it the alliaceous smell; 

 and the residuum of phosphorus; joined with the property 

 of not decomposing nitric acid; evidently prove, that it is 

 hidroguretted phosphuret of oxide of antimony. 



§ 7. Though alcohol impregnated with phosphuret of The compound 

 potash precipitates all metallic solutions, it does not always P'^'^'P"^'^^ ^' 

 form phosphurets of their oxides. In some cases the preci- Snot a"iays 

 pitates are oxides simply mingled with phosphorus, as occurs ^°'''" P^'*^?^"- 

 in the solutions of tin, zinc, cobalt, and manganese; in Sdr.'^ '^^^ 

 others they are phosphurets containing the metal in a pure 



* If this phosphuret have been some time exposed to the air, its 

 oxide absorbs carbonic acid, and the nitric acid then extrisates a 

 gas, which the operator might at first be tempted to take for nitrous 

 gas, but it has neither its smell nor its mtilant appearance. 



2 B 2 state. 



