Re: Strange units
"14 pounds to a stone (which is only used to weigh persons),"
A butcher's stone was 8 pounds.
Just when you thought you'd gotten your head around it all.
As for the distances or weights - I lived through the metric conversion in au/nz. ('73-75)
As kids we simply became bilingual in measurements (except fahrenheit - those are still alien).
Anyone ten years younger speaks metric-only, anyone ten years older is bilingual in decimal currency/£sd too.
The UK is metric in all but name. The road signs - posted in miles - are at km and metre multiplier intervals (and the engineering ones ARE in metric). The USA is the same.
The issue isn't that that metric is "different", but that under the old system there are _too many_ different units of measurements with strange multipliers between them. Rods, chains, perches, poles, yards, paces, feet, inches, miles, furlongs, leagues, fathoms, knots being just one set of examples.
And then there's the problem that there are different measurement units WITH THE SAME NAME - 6 different competing pounds/ounces over recent history. 2 actively used different measures with differing pints, fluid ounces, quarts and gallons.
And to cap it all off - going further back EVERY COUNTRY had its own unique sets of measurements. You can't standardise for widespread commerce in that kind of environment and whilst a country _might_ be large enough to try and say "our measures are good enough for us", this becomes at least as large a barrier for selling things OUTSIDE the country as for anyone on the outside attempting to sell things into the country.
You can see a similar effect with cars - there are three world car standards - UN(LHD) UN(RHD) and USA(LHD) - USA carmakers are now crying it's "unfair" that they are required to conform to UN(LHD) standards to sell their vehicles in the rest of the world and that the rest of the world should conform to USA(LHD) standards - which were mostly enacted as way of erecting a trading barrier to imports without breaching GATT rules in force at the time and had the effect of creating a captive market.
Most recently the US government has been trying to make out that requiring vehicles comply with "rest of world" safety standards before being sold in 3rd party countries is an illegal tariff barrier and they will take punitive action against countries that block imports on that basis. I wouldn't be at all surprised if they start pulling this against countries that drive on the left hand side of the road and require that the steering wheel be on the right hand side of the car (for obvious safety reasons)
And of course it wasn't so long ago that if you serviced cars you needed at least 4 different sets of tools to handle the differing standards used by the manufacturers (Acme, Whitworth, UNC, UNF, 4 different UK types, metric, etc etc etc)