United States customary units ounces. The fluid ounce derives its name originally from being the volume of one ounce avoirdupois of water, but in the US it is defined as of a US gallon. Consequently, a fluid ounce of water weighs about 1.041 ounces avoirdupois. The saying "a pint's a pound the world around" refers to 16 US fluid ounces of water weighing approximately (about 4% more than) one pound avoirdupois. An imperial pint of water weighs a pound and a quarter (20 oz). There are varying standards for barrel for some specific commodities, including 31 gal for beer, 40 gal for whiskey or
Canal pound called these "mule drinks", since the mules would drink from the water flowing over the towpath. Informal overflows were often replaced by a waste weir or lined with concrete or masonry to make a more "permanent" spillway. If the pound was many miles long, sometimes the canal would be designed with stop gates, so that if there was a break in the canal the whole pound would not lose all its water. Isolating the break would allow the company to make repairs sooner. For instance, on the 14 mile level of the Chesapeake and Ohio canal, there were stop gates