. Elements of modern chemistry . FiG. 12. duced. The hydrogen evolved is made to traverse the tubeCB, which is filled with fragments of chloride of calcium ; afterhaving been dried by this substance, which is very avid of^^ water, the gas escapes by the tube a, the end of which is drawn outto a point. The jet of gas islighted, and burns with a paleflame. A bell-jar, D, is nowheld over the burning jet, andthe sides of the glass soon be-come covered with dew, thedrops of which unite and rundown to the edge of the jar. Thisis water, and it is formed by thecombustion of the hydrogen ; thatis, by i
. Elements of modern chemistry . FiG. 12. duced. The hydrogen evolved is made to traverse the tubeCB, which is filled with fragments of chloride of calcium ; afterhaving been dried by this substance, which is very avid of^^ water, the gas escapes by the tube a, the end of which is drawn outto a point. The jet of gas islighted, and burns with a paleflame. A bell-jar, D, is nowheld over the burning jet, andthe sides of the glass soon be-come covered with dew, thedrops of which unite and rundown to the edge of the jar. Thisis water, and it is formed by thecombustion of the hydrogen ; thatis, by its combination with theoxygen of the air. 3. A jet of hydrogen may belighted by holding in it a tuft ofasbestos which has been dippedin platinum black, that is, finely-divided platinum. The con-densation of the hydrogen in the pores of the finely-dividedmetal is so rapid that the platinum becomes heated to redness,and then ignites the Fig. 13. HYDROGEN. 53 4. A tube filled with hydrogen may be held in the verticalposition, bottom upwards, without the gas escaping rapidly bythe inferior opening. If the tube be inclined, the hydrogenoverflows and escapes upwards through the air. It may thenbe received in a second tube held vertically above the first,which is inclined more and more (Fig. 13). The passage ofthe gas into the upper tube can be demonstrated by approach-ing to the latter a lighted taper, when the hydrogen will burnwith a faint explosion. Before igniting or collecting hydrogen escaping from a gen-erator, it should always be ascertained that the whole of the airhas been expelled, otherwise dangerous explosions may result. 5. The explosions may take place with the production of aharmonious sound, if they are made to succeed each other
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Keywords: ., bookcentury1800, bookdecade18, booksubjectchemistry, bookyear1887
