But metric measurements are based on an estimate of the world's circumference made in the 1790s! What sort of basis is that, I ask you!

Some while back, I read a story, only vaguely remembered, about a town in England that had posted their speed limit signs in km/hr. When asked if this meant that England was at long last converting to the metric system, somebody (local official, mayhap? the Queen?) is reputed to have said "Do you honestly think we'll ever adopt a measurement system invented by a people that have to say 'three twenties and seventeen' for 77?"

But the way weight and volume correspond in the metric system sure is useful and cool. Makes it easier to guess how much my hot tub weighs when full, which is very important, for reasons I'll not go into here.