_Qu._ 10. Is not Flame a Vapour, Fume or Exhalation heated red hot, that is, so hot as to shine? For Bodies do not flame without emitting a copious Fume, and this Fume burns in the Flame. The _Ignis Fatuus_ is a Vapour shining without heat, and is there not the same difference between this Vapour and Flame, as between rotten Wood shining without heat and burning Coals of Fire? In distilling hot Spirits, if the Head of the Still be taken off, the Vapour which ascends out of the Still will take fire at the Flame of a Candle, and turn into Flame, and the Flame will run along the Vapour from the Candle to the Still. Some Bodies heated by Motion, or Fermentation, if the heat grow intense, fume copiously, and if the heat be great enough the Fumes will shine and become Flame. Metals in fusion do not flame for want of a copious Fume, except Spelter, which fumes copiously, and thereby flames. All flaming Bodies, as Oil, Tallow, Wax, Wood, fossil Coals, Pitch, Sulphur, by flaming waste and vanish into burning Smoke, which Smoke, if the Flame be put out, is very thick and visible, and sometimes smells strongly, but in the Flame loses its smell by burning, and according to the nature of the Smoke the Flame is of several Colours, as that of Sulphur blue, that of Copper open'd with sublimate green, that of Tallow yellow, that of Camphire white. Smoke passing through Flame cannot but grow red hot, and red hot Smoke can have no other appearance than that of Flame. When Gun-powder takes fire, it goes away into Flaming Smoke. For the Charcoal and Sulphur easily take fire, and set fire to the Nitre, and the Spirit of the Nitre being thereby rarified into Vapour, rushes out with Explosion much after the manner that the Vapour of Water rushes out of an AEolipile; the Sulphur also being volatile is converted into Vapour, and augments the Explosion. And the acid Vapour of the Sulphur (namely that which distils under a Bell into Oil of Sulphur,) entring violently into the fix'd Body of the Nitre, sets loose the Spirit of the Nitre, and excites a great Fermentation, whereby the Heat is farther augmented, and the fix'd Body of the Nitre is also rarified into Fume, and the Explosion is thereby made more vehement and quick. For if Salt of Tartar be mix'd with Gun-powder, and that Mixture be warm'd till it takes fire, the Explosion will be more violent and quick than that of Gun-powder alone; which cannot proceed from any other cause than the action of the Vapour of the Gun-powder upon the Salt of Tartar, whereby that Salt is rarified. The Explosion of Gun-powder arises therefore from the violent action whereby all the Mixture being quickly and vehemently heated, is rarified and converted into Fume and Vapour: which Vapour, by the violence of that action, becoming so hot as to shine, appears in the form of Flame.