FuKL Oils kor Pump Irrigation 405 



tion. The price of this oil is about i^2.80 a barrel (42 gallons) at Cali- 

 lornia refineries and $4.20 a barrel at Arizona main line points. 



boili;r fuel oil 



In the refining of asphalt base oils, the greatest bulk of the crude 

 oil is left as boiler fuel oil after the more valuable constituents have 

 been removed. In Arizona, boiler fuel oil is used almost exclusively 

 as fuel for steam plants. It is tried occasionally in diesel and Brons 

 engines, but it is poor judgment to use this oil in any internal-combus- 

 tion engine. The gravity runs from 14° to 18° B. Its cost at the 

 present time is about $1.85 to $2.00 a barrel (42 gallons) at California 

 refineries, and $3.40 a barrel in Arizona. 



Much boiler fuel oil has been shipped into .Vrizona from Texas 

 during the past two }ears, depending on the relative prices in Texas 

 and California. 



Mexican oil is received at Galveston and reshipped. It will be an 

 important factor in steadying the price of Texas oils. Mexican crude 

 is heavy, usually about 14° B., and contains a very low percentage of 

 light oils. 



One disadvantage to the purchaser in buying heavy oil is tiic <lil- 

 ficulty of handling it. A carload of 18'^ B. oil received recently at 

 Casa Grande was so viscous that it required 98 hours of pumping to 

 unload the oil, am! the cost of unloading was over $150. Had steam 

 for heating the oil been available, the cost could have been reduced. 



TESTS 



The qualities of petroleum oils for whicli tests are applied ordi- 

 narily are as follows : 



1. Gravity 5. Solidifying point 



2. Flash -point 6. Sulphur content 



3. Burning point 7. Water and sand content 



4. Boiling range 8. Thermal value 



gravity 

 There are two scales in use for expressing gra\ity, the Baume 

 scale and the standard decimal scale. In the former the gravity of 

 pure water is taken at 10°, in the latter at unity, that is, 1.000. Gaso- 

 line in the Baume scale is about 56'' to 60°, in the decimal scale it is 

 about .750, showing that gasoline is about three- fourths as heavy as 

 water. 



