In England, one fluid ounce is equal to one ounce or 437.5 grains of water and is equal to 1/20 of an imperial pint.
In the USA, one fluid ounce is equal to one ounce of wine (or so the story goes), 1.04158 ounces or 455.6 grains of water, 1/16 of a US pint, or 29.57 cubic centimetres.
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