Restoring Old Silk Ribbons
Fire is the gift of Heaven to man, and by U.s use he is distinguished from all other ani mals. Not to know the nature and properties of this valuable agent is a voluntary surrender of our dignity. Fire assumes two forms, called slow combustion and quick combus tion; in botb cases the material burned gives out beat anG disappears, nothing bappening to attract ,he eye of Ii casual observer; never theless, slow and quick combustion produce very remal'lmb1e results. Wben substances are burniog that
... es are burniog that are only red hot, tbey are un going tbe slow combustion. ; but when tbey burn with flame, that is called the quick com bustion. Illustrations of this difference are eommon enough. A cA.ndle burns with /la.me -blow it out, and the wick cont.inues to hurn for a time red hot. Note tbe difference of re sult: while there iR fl:Lroe thefe is plenty "f light, and no smoke ; wllcn t.he flame is ,'x tingnished, Ii strong', odorous yapor arise�, fa miliar to all. A IDan smokes a segar, and it. is undergoing the slow combustion-tbe fra grant vap;)r is his delight-but if the same be put into tbe fire, or hurned with flame, tbere is no smell of burning tobacco. In ordinary conversation the slow combustion is termed «smoldering," anrl is alwa. ys known to he taking place by the familiar" smell of fire" l1� one of the results. Tbis smell of fire is, in truth, the smell of the vapors arising from a suhstance burning witbout flame; agreeahle when eorning from tobacco or a �eented past.il, but quit. e t.be reverse when eoming tram fat, oil, or tbe like. From want. of air, quick cmn· bustion may sink into tbe slow combustion: smouldering bodies, on the contrary, burst into flame by the ready admission of air. Strictly speaking, tbe slow comhustion is but an im perfect burning of the ( ' onsumeable sllhst.anee, becmIse the v9,por that ariseR is itself cap9.hle of hurning again; but if tbe quick combus tion take pLace, the products of the flame can not he again igni ted. We should al ways burn the coal hy quick eombustion in firebrick lined grates; iu fact, not as tbe smoker does with bis tobacco, make a rare fume-consume it by slow instead of tbe quick combustion.