MANUFACTURED GASOLINE AND MOTOR SPIRIT 39 



gasoline to the air as much as- possible so that the air mil become 

 fully saturated with the gasoline vapor producing gasoline gas. 



THE MIXER is a device for maintaining the proper mixture of 

 gasoline vapor and air. Gasoline consists of many different 

 compounds (See Art. 88). Each compound has a certain rate 

 of evaporation, at a given temperature. The lighter portions 

 of the gasoline evaporate more quickly than the heavier por- 

 tions. This means that for some time after each refilling of 

 the carbureter the air is more completely charged with vapor 

 than is the case later when the lighter portions of the gasoline 

 have evaporated and only the heavier portions remain in the 

 carbureter. The purpose of the mixer is to keep the gasoline 

 gas, i.e., the mixture of air and gasoline vapor, the same at 

 all times. 



The gasoline gas machine is used successfully, not only to 

 furnish gas for lighting purposes, but also for cooking in a gas 

 range exactly as city illuminating gas is used. It is found 

 in many country residences. Only 88B. gasoline can be used 

 in these machines. 



VII. MANUFACTURED GASOLINE AND MOTOR SPIRIT 



46. Importance of Gasoline. Up to about the year 1900 

 kerosene, or illuminating oil, was by far the most important 

 product of petroleum. Only a certain percentage of the crude 

 oil generally from 30 to 50 per cent. could be refined as 

 illuminating oil and about 20 per cent., as gasoline. There was 

 a good market for the kerosene but only a light demand for the 

 gasoline. As a consequence, kerosene sold for a higher price 

 than did gasoline. With the general introduction of electric 

 lighting in towns and cities the demand for kerosene fell off; 

 while, at the same time, with the perfecting of the automobile 

 and the gasoline engine's coming into general use, the demand 

 for gasoline increased greatly. About 1910 the demand for 

 gasoline became greater than the supply, and the price became 

 higher than that of kerosene. This increased demand for 

 gasoline has led oil refiners to adopt the plan of putting nearly 



