292 GENERAL SCIENCE 



tides of carbon during their oxidation. The gas lamps 

 which use some type of the Bunsen burner have a mantle 

 over the flame. The Bunsen burner mixes the oxygen 

 of the air with the gas before it gets to the flame, and 

 complete oxidation of the carbon particles occurs so 

 quickly that not much light is produced, but a very hot 

 flame results. This flame brings the white mantle to a 

 glowing white heat and a very bright light is produced. 

 The Bunsen burner can be used for burning gasoline, 

 acetylene gas, or natural gas. 



Incandescent electric light bulbs make light because the 

 fine wire, carbon, or tungsten filament in them is made 

 white-hot by the electric current passing through. In the 

 street corner arc light a glowing arc of white-hot carbon 

 vapor and the glowing ends of the carbon make the light. 

 There are two sticks of carbon in the lamp, and after the 

 current is turned on the ends of the carbon are automat- 

 ically pulled apart and then the electric current crosses from 

 one to the other by vaporizing the carbon. While the 

 carbon is being vaporized, it is made white-hot. The arc 

 lamps can be made to give a light of 500 candle power. 



200. Illuminating Substances. Candles are made of 

 tallow, sperm whale oil, or paraffin, by dipping the wicks 

 into the melted oil or by pouring it into molds containing 

 the wicks. 



Carbon oil and gasoline are made by distilling crude 

 petroleum. Paraffin is also obtained from petroleum. 



Natural gas is obtained by drilling into the earth in 

 the same manner as for petroleum and then collecting 

 the gas in storage tanks, from which it is piped to buildings 

 for heating, cooking, and lighting. Natural gas is not 

 very widely distributed and its use is largely restricted 

 to the regions where it is found. 



