NATURAL GASOLINE 539

 At the close of the year, however, there was relatively little difference
between the price of this grade of natural gasoline and that of /
refinery gasoline. The relative price trends of natural gasoline and
U.S. Motor gasoline over a 10-year period are shown in figure 46.
 Both natural-gasoline manufacturers and refineries are faced with an oversupply
of the more volatile fractions, particularly butane. Butane is a very desirable
constituent of motor fuel, but its vapor pressure limits its inclusion in
motor fuel according to the design of automotive fuel systems. As this equipment
is developed to permit the use of motor fuel having greater volatility, the
butane content of motor fuel will be increased appreciably, to the economic
advantage of both the natural-gasoline manufacturers and refiners. It appears,
however, that this development will be slow. Although mcreasmg amounts of
the volatile fractions are being distributed as "bottled gas" and for gas
manufacturing, the market is so far short of consummg the total possible
supply that the industry must depend on utthzation in motor fuel as the principal
market for these fractions.
z
' 5
FIGURE 46.—Trends in the average refinery price of U.S. Motor fuel
(Oklahoma) and in the average value
of natural gasoline at plants. 1923—32.


 Storage of gasoline as a/actor in the market.—With limited facilities
for storage at plants, manufacturers cannot accommodate the excess production
durmg periods of declining seasonal demand. As a result, natural gasoline
is first to enter the market as distress gasoline with attendant recessions
in prices, which in turn tend to weaken the price structure of motor fuel.
 To balance supply with fluctuations in market demand there is a growing
tendency to store increasing quantities of light fractions durin~ the summer
to be blended with motor fuel during the winter, in which period present
automotive fuel systems can utilize successfully products with much higher
vapor pressure.
 During the year there was also a trend toward blending at bulkstation plants.
This practice not only provides desirable storage facilities but also has
the economic advantage of entailing only one freight charge compared with
the double charge when the product is transported to the refinery and out
again to the consuming market.
 Grading system.—An important influence on marketing has been the closer
evaluation of the composition of natural gasoline conforming