GASOLINE LAMPS AND GASOLINE GAS MACHINES 35 



asbestos wool. This asbestos wool is saturated with alcohol 

 just before being placed upon the small U-tube. This 

 alcohol is lighted. The flame heats the small U-tube quite 

 hot. The valve is now cautiously opened so that gasoline 

 may flow. As the gasoline flows through the heated U-tube 

 it is vaporized. This gasoline vapor mixes with air as it 

 passes into the MIXER. This mixture of gasoline vapor and 

 air, or GASOLINE GAS as it is called, is lighted as it escapes 

 through the burner. 



As soon as the lamp is lighted the asbestos is removed. 

 The heat from the burning gasoline keeps the small U-tube 

 hot, thus vaporizing the gasoline as long as the lamp burns. 



The purpose of the small U-tube is to heat the gasoline and 

 vaporize it; it is the VAPORIZER. The purpose of the large 

 U-tube is to mix the gasoline vapor with air; it is the MIXER. 



42. The Need of a Mantle. The flame is, however, a dis- 

 appointment to those who expect much light. But by hold- 

 ing your hand above the chimney, you will see that a great 

 deal of heat is being produced. Before much light can be 

 obtained from this lamp we must place a MANTLE over the 

 burner as shown in Fig. 17. This mantle consists of a small 

 inverted sack about 1 in. in diameter and 4 in. long. It is sus- 

 pended from a metal frame which sits over the burner and 

 holds the mantle in place. 



The mixture of gasoline vapor and air is burning within the 

 mantle. The mantle does not burn but glows, because it is 

 heated white hot, exactly as a piece of iron glows when heated 

 to white heat in a blacksmith's forge. The material out of 

 which the mantle is made is now said to be heated to INCAN- 

 DESCE*NCE. Such lamps as this consequently are said to be 

 INCANDESCENT lamps. The word incandescence comes from 

 two Latin words: in, meaning in; and candesco, meaning to 

 grow hot. 



This lamp involves principles employed in the burning of 

 gasoline in all gasoline lamps, stoves, and gasoline engines. It 

 is capable of giving as much light as 100 or 150 candles or 10 



