2003-01-19 Rowlett seems to think that the extra 2 gallons was used to prevent spillage, not as a bonus when 40 gallons was purchased:
barrel (bbl or bo) [2] a commercial unit of volume used to measure petroleum. By international agreement a barrel of petroleum equals 42 U. S. gallons, which is about 158.987 liters. The symbol bo (barrel of oil) is used for this unit in the petroleum industry. The petroleum barrel originated in the Pennsylvania oilfields (the first commercial oilfields) in the late nineteenth century. Apparently, 40-gallon barrels were increased to 42 gallons to provide insurance aganst any spillage or underfilling. By coincidence (it seems), this unit is the same size as the traditional tierce, a wine barrel. John >From the French journal "Le Syst�me M�trique" I learned that the barrel of 42 US gallons goes back to about 1850 when the only oil well was in Pennsylvania. Customers arrived at the well head with their own barrel to take away the kerosene that they bought. If they bought 40 gallons they were given a bonus of another 2 gallons. I have not been able to verify this explanation. 42 US gallons = 158.99 litres -- Joseph B. Reid 17 Glebe Road West Toronto M5P 1C8 Telephone 416-486-6071
