OK.The problem here is that 16 US fl.oz weighs > 16 oz,due to:

"In 1824, the British abandoned both the Ale and the Wine gallons in favour of the Imperial gallon, based on the volume of 10 pounds of water (which works out at 277.41945 cu in).

America, by this time, had already standardised on the Wine Gallon of 231 cubic inches (strictly speaking, this was defined as the volume of a cylinder 6 inches long and 7 inches in diameter, or 230.9070 cubic inches)."

Gallons were divided into 8 pints

In US, 1 pint = 16 fl.oz...... 128 fl.oz/gallon

In UK, 1 pint = 20 fl.oz...... 160 fl.oz/gallon

As stated, 1 UK gallon weighs 10 lb

but

1 US gallon weighs 8.33 lbs.....(not the expected 8.0)

1 UK fl.oz = 1.73387195625 cu.in

1 US fl.oz = 1.8039609375 cu.in

1 ounce, fluid or liquid (U.S.) = 1.041 British fluid ounces

http://mathforum.org...view/52591.htmlhttp://www.infopleas...a/A0001661.htmlhttp://dictionary.re...de/weights.htmland an unusual source.....!

http://www.bestfish.com/convert.htmlThere are many more.

As for the the saying. Yes I can accept there is artistic/poetic license at work, but it's not a saying that is used "all the world around" (for obvious reasons). Perhaps it's been corrupted over the years and the word "New" dropped...