ECN Forum Forums General Topics of the Trade General Discussion Area Metric Inches

In for a penny, in for a pound, Paul!...
Originally, 'gallons' meant a multitude of quantities, depending on what was being measured; corn, wine, ale etc. In 1706 during the reign of Queen Anne, [ftatute #5], the liquid gallon waf redefined af 231 cubic inchef, or 3" x 7" x 11" exactly.
This is the US gallon.

In 1824, [ William IV ] the British decided to parody the French metric idea, [ oh! not them again! ] and redefined the Gallon as 10 pounds of water measured with brass weights at 30" of mercury barometric pressure and at 62 deg F. ambient.
Some slight later tweaks were made, but:-
This is the Imperial Gallon.

These are liquid measures. There are still US 'dry' gallons for corn etc. in current use I believe. I'm not sure the Imp. Gallon is any longer a legal measure in the UK?

Alan

edit to correct number.


[This message has been edited by Alan Belson (edited 08-15-2006).]

Possibly not since gas pumps were changed to liters a few years ago, but you're getting into a big debate there which has formed much of the argument over the "Metric Martyrs" case (traders prosecuted for continuing to sell their wares in English units instead of metric).

See the various articles here for details:
http://www.bwma.org.uk/

I imagine the US will be the last country using the "English" units. There are still plenty of folks here who think it is a commie plot or something "French".
I have started using "C" for my pool temperature, mostly because the lab grade armored thermometer is marked that way. It is easier though. 27 is too cold and 31 is too hot. I am working on a floating thermometer that outputs on 4 LEDS.
27 and below blue
28 yellow
29 green
30 and above red

OK here is one I love:
What is heavier a pound of feathers or a pound of gold? - Oh we have all heard that one - The answer is neither right! WRONG! A pound of feathers would be measured in pounds avoirdupois (16 ounces to the pound - 453.6g) while the gold would be measured in pounds troy (for precious metals) at 14 troy ounces to the pound (373.2g). Just when you thought you had heard it all.
Cheers Ann

I recently did a plumbing job for a friend... I had to buy: 25m of 15mm copper pipe with associated solder fittings, for connecting things: a 1/2" spigot with a 3/4" hose connector, several sets of 15mm solder to 3/8" and 1/2" threaded adaptors, and for the boiler two 3/8"-1/2" adaptors.

Or at school... once we needed a Whitworth threading set... metric threaders exist by the dozen, but the entire technical school of 3000 students (ustria's largest school) has only one Whitworth set...

Never heard of Whitworth thread size, is that a speciality measurement?

When I was in high school in the mid 70's Canada was just changing from inches / feet to Metric so I am sort of at home in both.

My nieces that are in school now all use metric and convert to Imperial only when necessary.

It's an old British system, common on cars and other machinery right up until the 1960s. I still have a set of Whitworth wrenches and sockets that my father bought 50+ years ago.


http://www.enginehistory.org/british_fasteners.htm

The derived BA (British Association) sizes were also the standard for smaller nuts and bolts in electrical equipment until displaced by metric.



[This message has been edited by pauluk (edited 09-02-2006).]

Whitworth's rifle was a strange beast. In 1853, in a characteristic burst of energy and design flair, he carefully studied the subject and came up with a 44 calibre muzzle loading, hammer and cap, 500 grain bullet, black-powder rifle of immense range, bullet stability, ease of manufacture, accuracy and low weight - with a rifled hexagonal bore!
And he had a state of the art factory in Manchester to build them in. The rifle was baulked at by the War Office, [ because of an inherent black powder fouling problem ] and they ordered a competitor's conventional rifle instead.

The 'Whitworth' was a one-shot marvel, ideal for snipers but not infantry. His rifle swept the board at shooting competitions* though, as one would expect.

[* These contests were a regular feature of Victorian England, with gigantic prize money, akin to a lottery jackpot today. There were no gun laws then and shootists regularly travelled to these contests by train or omnibus with their guns open to view and loaded ].

When his design was rejected, Whitworth bought a building right opposite the War Office and spent many snarling hours glowering angrily across the street through a window at his detractors.

The French adopted his rifle, of course.


Alan