Chemical lecture experiments . The stem of the funnel isconnected by means of a rubber tube tothe gas-cock. A small heap of gunpowder,about 15 mm. in diameter, is placed in thecentre of the wire gauze, care being takenthat no small particles of the powder arescattered on the gauze away from themiddle of the heap. After protecting theapparatus from strong draughts, the gasis turned on and a match brought downfrom above until the gas is ignited. Itburns with a large flame, and the gun-powder remains on the wire gauze uncon-sumed. Ordinary matches may be thrustsuddenly through the flame, and thei
Chemical lecture experiments . The stem of the funnel isconnected by means of a rubber tube tothe gas-cock. A small heap of gunpowder,about 15 mm. in diameter, is placed in thecentre of the wire gauze, care being takenthat no small particles of the powder arescattered on the gauze away from themiddle of the heap. After protecting theapparatus from strong draughts, the gasis turned on and a match brought downfrom above until the gas is ignited. Itburns with a large flame, and the gun-powder remains on the wire gauze uncon-sumed. Ordinary matches may be thrustsuddenly through the flame, and their heads laid on theheap of gunpowder, without being ignited. On slowlyturning down the gas, the flame will diminish in size andsoon play over the surface of the gunpowder and cause itsignition. In repeating the experiment, care should be taken to allowthe gauze covering to become perfectly cold, and in no casemust the powder be added from the bottle or other container,but rather from a small piece of paper. In introducing the. Fig. 134 STRUCTURE OF FLAME 331 phosphorus matches, care should be taken not to disturbthe heap of gunpowder and scatter the grains. While theexplosion of such a small quantity of gunpowder is not dan-gerous, the eyes and face should be protected from any pos-sible accident. 5 cm. funnel; fine wire gauze ; gunpowder ; shields or eye-glasses. (b) A pin or needle is thrust through a match just belowthe head. On allowing the match, supported on the needle,to hang down the tube of a Bun sen burner, the gas may belighted and the match remain unlighted in the centre of thenon-luminous flame. The match, to avoid touching the edgeof the cone, and thereby becoming ignited, should be soplaced that it is as near as possible to the centre of theinner cone. A Bunsen burner giving a perfect flame isnecessary for this experiment. 4. Pictures of flames with asbestos paper. — An interest-ing study of the temperature zones of an ordinary Bunsenflame may be made by depres
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectchemist, bookyear1901
