A Gallon is a unit of measure of volume for liquids, used in the community of Anglo-Saxon countries. The gallon of the United States, is not equal to the gallon of the United Kingdom. This is because, Britain began by indexing the gallon (known as the imperial gallon) to the volume of 10 pounds of water. While in the United States, the gallon was indexed to the volume of a cylindrical container (intended to contain wine), 6 inches long by 7 inches in diameter. Milk bottles marketed in the United States usually weigh 1 gallon (about 3.8 liters), while in countries with the international metric system these bottles are usually sold per liter.
A Liter corresponds to the amount of liquid that fits exactly inside a cube with 1 dm of edge. Since the density of water is approximately 1 kilogram per liter, this almost equivalence makes it easy to move from one measurement system to another (in the case of water). In other substances, whether liquid or not, the passage from one unit of measurement to another, is possible only if we know its density. As a matter of curiosity, know that filling a tub to take bath causes that approximately 265 liters of water are consumed, and that a liter of gasoline is enough to contaminate 700 thousand liters of water!
`L=text(US gal lqd) / 0.26417`