High School Chemistry . nd observe itsflame carefully. Note how manyparts there are in it. Take a nar-row bent glass tube, about four orfive inches long, and thrust one endof it into the dark cone in themiddle of the flame, as in Fig. to light the vapours which risethrough the tube. Repeat the ex-periment but use a Bunsen burnerinstead of the candle Try, both when the holes at the base are open and when they areclosed. Why can you not get this result with a commoncoal oil lamp? Try a lamp that has a circular wick. Explanation.—It is customary to speak of a flame asbeing made up of three
High School Chemistry . nd observe itsflame carefully. Note how manyparts there are in it. Take a nar-row bent glass tube, about four orfive inches long, and thrust one endof it into the dark cone in themiddle of the flame, as in Fig. to light the vapours which risethrough the tube. Repeat the ex-periment but use a Bunsen burnerinstead of the candle Try, both when the holes at the base are open and when they areclosed. Why can you not get this result with a commoncoal oil lamp? Try a lamp that has a circular wick. Explanation.—It is customary to speak of a flame asbeing made up of three parts ; these are—ist, the centralcone, consisting of gas that is not ignited; 2nd, theluminous mantle in which combustion is going on; this isthe chief light giving part; 3rd, the outer mantle whichis usually but slightly luminous and in which combustionof the gaseous substance is completed. In the centralcone the gas is still unburned. In the candle flame it isformed by the fatty constituents of the wax or tallow. Fig. 37. IGNITION. 151 being drawn up through the wick from the httle reservoirof melted matter surrounding it, and these are freed at thetop of the wick in the form of vapour by the heat of thesurrounding flame. As no oxygen is in contact with thisgas it will not burn. A current of air is, however, beingdrawn into the vapour at the base of the flame around thewick, and the oxygen of this air causes the outer layer ofthe central cone to undergo constant combustion, withthe result that the carbon particles in this mantle becomeincandescent. In the outer layer or mantle of the flame,air has become freely mixed with the vapour, and thisvapour has been largely deprived of solid carbon particleswhile it was in the middle (luminous) mantle, so that itnow burns with a nearly non-luminous flame. Themiddle and outside mantles correspond respectively to aBunsens flame with the holes at the base of the burnerclosed and then open. The central cone is called thatof non-comb
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