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parent and colourlefs. All tills fhould be cloneunder water. What remains in the bag is amixture of black carbonaceous matter, with agood deal of the red incombuftible oxyd ofphofphorus already mentioned. Care muff betaken in doing this not to get any of the phof-phorus beneath the finger nail, which mightoccafion a dangerous and painful burn. Theleather will not ferve a fecond time.
Another way is by diftillation. Phofphorus isperfectly volatile at a heat of about 20c 0 and itriles in the fecond dillillation quite pure andtranfparent. In doing this, all accels of airfhould be prevented, as the heat required tofublime it much exceeds that at which it takes firein the air. The air within the velfcl is fpeedilydeoxygenated by tlie action of the phofphorusat a common temperature, and of courfe nocombuftion can take place when the phoiphorusis further heated in this fame air.. Or, thephofphorus may firft be melted to the bottomof the retort by hot water, and the latterdifplaced by azot or hydrogen, (in which phof-phorus is equally uninflammable) and then aheat applied fufficient firlt to melt and then tofublime the phofphorus.
Another mode of purifying it is to melt it innitro-muriatic acid, and to lhake it thoroughlyin the acid, whereby on Itanding again itconcretes into a very white tranfparent mafs.The red oxyd of phofphorus is feparated in thisprocefs and is converted into phofphoric acid.This method however does not appear to be fogood as the firft mentioned.
Phofphorus when newly purified is nearlytranfparent and of a waxy confidence, butwhen kept in water it foon becomes coveredwith a reddilh-white opake cruft. It is in-foluble in water. Its fpecific gravity is 1.77.
The moft remarkable phenomena relating tophofphorus are thofe that occur during itscombuftion. When a ftick of phofphorus islimply expofed to the air, if the temperature beabove 45 0 , it conftantly fends off a whitevapour of a very ftrong unpleafant fniell, fome-what like that of garlic, which is more copiousjutd denfe in proportion to the temperature,rhis vapour in the dark is feen to be a bluelambent flame, and it continues to he emitted
rom the phofphorus for a great length of timexvtth httle apparent alteration, and withoutgivmg °ut any lenfible heat. Hence it is that1 l C ■ crs are traced by rubbing a ftick ofp 10 p torus on a board, or any rough furface,
icy are ma e luminous by the minute quantity
of phofphorus abraded, when expofed to theair. This however is a real though flow com-buftion, and in time the whole of the phofphorusis partly wafted away in luminous vapour, andpartly converted into acid on the fpot, and thelight ceaies. When a piece of phofphorus isput into a filver fpoon and held near a fire orcandle, the white vapour becomes extremelydenfe and copious, the phofphorus melts atabout 99 0 , and at 14H 0 it takes fire and burns witha very bright greenifh white flame and heavywhite fmoke. No refidue is left in the fpoon,but if the fmoke is received, into any veffel itcondenies on cooling into a very four liquid,which is the phofphoric acid. Thus then itappears that there are two modes of combuftionoi phofphorus, one a flow combuftion, withfcarcely any fenfible heat, and in which muchof the phoiphorus is flowiy volatilized by thefurrounding air; and the other a rapid com-buftion with vivid light and intenfe heat. Theformer begins at the temperature of from 40°to 45 0 (in the atmofphere) and whilft thephofphorus remains lolid; the latter occurs atthe heat of about 148° and after fufion. Theformer is not dangerous to the touch, but thelatter produces a very rapid deftruftion of thefkin and flefh, fo that phofphorus fhould alw'aysbe handled with great caution, as very feriousburns have arifen from careleffnefs in thisrefpeef.
Phofphorus when very pure diffolves in al-cohol though very fparingly. As it diffolves., theliquor takes the peculiar unpleafant fmell ofphofphorus. e This folution is not of itfelfluminous, but if a drop of it is let to fall ona little water at the bottom of a glafs veffel inperfect darknefs, the moment it touches thewater a faint blue lambent flame is feen toundulate on the furface and gradually to filthe veffel. If the air of the veffel is changedby blowing into it, the fame phenomenon isrenewed repeatedly till all the phqfphorus isextrafted from the mixture. In like manner if.a wetted feather be dipped in the phoiphorizedalcohol, the air above the point of contadfimmediately becomes luminous. In thefe ex-periments there appears a kind of doubledecompofition, the phofphorus uniting with theatmofphere, and the alcohol with the water,and the heat excited by the mixture of thefetwo liquors doubtlefs favours the decompofition.
Oil of turpentine and the other- effential oils’diffolve phofphorus with more facility and ingreater quantity than alcohol. If a little of
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