At 10:03 AM 5/22/2007, you wrote: >Rob Kimberley wrote: > > Happy memories... > > > > I remember being switched half way through my "A" Level Physics course from > > cgs to MKS in 1968. > > > > Legal here in UK to show weights & measures in shops in both metric and > > imperial systems. Fuel at petrol (gas) > stations sold in litres, and distance > > on roads still shown in miles (!!). Never did understand how the US gallon > > was smaller than the Imperial one though... > > > >Pretty simple, really, a US gallon is 4 quarts (as in quarters), an imperial >gallon is 5 quarts. > >The real question is when did the imperial gallon pick up the extra quart.
It never did, an Imperial gallon is also four quarts, just different quarts! The question really is how come the US quart is smaller than the Imperial one? The US Gallon has 128 pints, the Imperial has 160. The US Gallon is based on the Queen Anne gallon of 1706, also known as the 'Wine Gallon'. Speculating on the US Customary versus Imperial systems is a little difficult, as the Imperial system wasn't formalised until 1824, by which time the former US colonies paid little heed to what was going on in England! The Wine Gallon was essentially superceded for all purposes except the taxing of Wine in 1824, as was the older and more commonly used Ale Gallon of about 282 cubic inches. They were replaced by the Standard Gallon of 277 cubic inches, or more precisely, 10lbs of water at 62°F measured in air with brass weights. So in essence we see two divergent measurement systems which didn't converge again until 1852 (in the case of the nautical mile) and 1959 in the case of other units, particularly length. Weight, as I recollect, has always been the same. some time in the mid-19th century (after the standardisation of 1824) the British sent a 'pound' to the Americans who found it to weight the same as their pound. They also sent a couple of yards, but there was a slight difference. In 1893, the BIPM in Paris supplied standard metre and kilogramme bars to the US which were adopted by the administrative fiat of Thomas Mendenhall, Superintendent of Weights and Measures in the Treasury Department and they thenceforth became the standard for all measurements in the US, and since then the US customary units have been officially defined in terms of metric units. John >-Chuck Harris _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
