GAS IN THE HOME 



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nary burner, has not been previously mixed with air, 



a yellow flame results. This is a very wasteful type of 



burner. The Bunsen burner, in which 



air is mixed with the gas, gives a clean 



hot flame which is not very luminous. 



A combination of this type of burner, 



which produces much heat, with a 



mantle which glows when heated, gives us 



the Welsbach light. .Welsbach mantles 



are made from compounds of two rare 



metals, thorium and cerium, which when 



heated to a high temperature give the 



bright light we are so familiar with. 



Am, 



A Bunsen burner. 



Experiment. To show the advantage of the mantle in gas lighting. 



Connect a common fishtail burner and a Thorp gauge to the gas supply. 

 Light the burner and see how many cubic feet of gas per hour are 



Effect of gas appliance on cost of gas. Black = minimum ; Black and white =- maximum ; 

 M = mean cost per hour. 



