P II o

PHO

( 214 )

.dark. Water thoroughly purged of air byrecent and long continued boiling, will abforbat ^5° about a fourth of its bulk of the gas.

When this folution is heated, the gas isagain expelled, at a heat below boiling, un-altered, and as inflammable as before-

If the folution is expofed to the air it foonbecomes turbid, and depofits a confiderable■quantity of red oxyd of phofphorus, whilfthydrogen efcapes, which is now no longerfpontaneoufly inflammable. In time the liquorbecomes limply water containing a little oxydof phofphorus.

This folution of phofphuretted hydrogenwhen made with well boiled water does not-change the colour of litmus, and therefore isneither acid nor alkaline. It fpeedily altersmany metallic folutions, reducing the metal to.the ftate of a phofphuret. This is particularlyremarkable when added to the folutions offilver, mercury, and lead, which it immediatelyblackens and feparates a phofphuret of themetal, which in time is changed to a phofphat.

Phofphorus fcarcely if at all unites with anyof the three alkalies at any temperature.

With lime phofphorus unites by a moderateheat and forms a compound which has fomecurious properties. It may be made in thefollowing manner. k Put into a long dry thinphial about half a dram of well burnt powderedlime, then about half this quantity of phofpho-rus, and fill it with alternate ftrata of lime andhofphorus. Stop it loofely with a cork, andury it to the neck in hot land, and keep theheat to-a degree juft below rednefs till the limeis uniformly impregnated with the phofphorus,and is of an auburn colour. In this procefsthe phofphorus rifes in vapour through the lime,and a part unites with it into a phofphuret,but fome efcapes by the cork and burns off.When the procefs is finifhed, for which noexa£t rule can be given, prefs the cork in to.prevent the air from entering in cooling, andto keep it for any length of time the bottlefhould be inverted over mercury.

The phofphuret if duly prepared is friableand readily broken down in the bottle whencold by an iron wire, and at this point theprocefs fhould flop. If continued longer, toomuch of the phofphorus is expelled, and thephofphuret will not prefent the ufual appear-ances j if too little, the mats is hard.

When a quantity of this phofphuret is throwninto water about blood warm, it fvvells and

k •> An. Chim. tom. \xxv. p. 4,

° * Phil. Journ. 8vo. vel.

crackles, and bubbles mount up, which take. fire as foon as they reach the air, and burnwith a bright flafli and fnapping noife on thefurface of the water. This gas is phofphurettedhydrogen, the properties of which have beenalready defcribecl.

By a fimilar procefs phofphorus may be madeto combine with barytes, and when melted, itexhibits the fame phenomena.

Phofphorus appears to unite with charcoalduring the procefs of the' diftillation of phof-phorus by charcoal and phoiphorie acid. Thiscompound (according to Proull 1 ) is the fubftancethat remains in the leather bag when the impurephofphorus has been drained through it asalready mentioned, but it is befides mixed withfome uncombined phofphorus. It is red, anddoes not melt like pure phofphorus. Diftilledper fe in a clofe veflel the excefs of phofphorusfublimes at a moderate heat, and there remainsan ora ge red light flocculent mafs, apparentlyhomogenous, which this excellent chemift con-fiders as the true phofphuretted charcoal. Ifthe heat is raifed to rednefs molt of the combinedphofphorus is fublimed, and the refidue islittle elfe than charcoal.

If a little of the phofphuretted charcoal islaid on a red hot iron plate, the phofphorusburns firft, and forming phofphoric acid itmelts with and involves the remaining char-coal and preferves it from the further action ofthe fire. Cauftic potafli in folution boiled withthis compound produces no effedt upon it,which file vs how intimate is the chemical unionof the conftituent parts. It is probably thisfubftance that forms the red or black powderwhich fo often appears in many operations withcommon phofphorus.

Sulphur and phofphorus unite in feveralproportions, forming a very interefting com-pound, which is one of the moft inflammableand dangerous combuftibles that we are ac-quainted with. Phofphuretted fulphur was firftnoticed by Margraaf, afterwards by Pelletier,“*who lias {hewn the mode of combining them,and the great fufibility of the compound, andmore lately Mr. Accum" and Dr. Briggs 0 havegiven very interefting papers on this fubjeft.From all thefe fources the following particularsmay be collected. This fubftance may bemade by heating the phofphorus and fulphur inthe required proportions in water till the phof-phorus melts, which foon difl'olves the fulphurand forms a yellowifli mafs, which is the

™ Memoirs, &c. de Pelletier, tom. x.

6. * Do. vdi. 7.