In France you can also buy vegetables by the pound (une livre), but if course both of these are just shorthands for half a litre and half a kilo, respectively, they're not actually the old measures.

I was surprised, when I found out, how comparable many of those relics are. Many countries had a variation on a pint, a pound etc, that were in the same ballpark but never quite the same. I'd always presumed pre-metric Europe would have much wider variation in units. Maybe they stem back to the Romans, like £sd did.

You'd be surprised on milk - I'd say the commonest supermarket sizes are still really pints. Usually 2.272l (4.0 pints), and 2 and 6 pint equivalents. Posh variants like some organic, filtered etc are in 2.0 litre packs - mostly opaque so you don't notice the 4 pint capable pack with lower fill level. :)

Shoe sizes are infuriating. Would be nice to find a way to standardise, and have manufacturers agree on what size x means, as they've diverged wildly from reality.

> Fahrenheit does have some nice properties

Which exactly? Walter melting at 0°C and boiling at 100°C seems the most practical.

The main niceties are the increased granularity (nobody would use half °C in practice) and 100°F being the normal body temperature and a good landmark to relate to hot weather.

0°C is absolutely super practical and is imperative to have as a landmark. 100°C boiling water... it isn't really that practical in day to day use in my opinion (when was the last time you saw 100°C written on a device?). In the high temperatures the ones I care about in a practical sense are on the oven for cooking and on my soldering station, both much higher than 100°C anyway. The only time I care about boiling water temperature is when I am boiling water in which case I don't need a thermometer.

So I think 100°F is more interesting as a landmark than 100°C for intuiting temperatures. You can think of it as the percentage of how hot it is. But 0°C is more interesting than 0°F.

I don't understand why we want round numbers here. I know 40 C is "very hot" and for Americans that's 100 F. Using a rounder number makes absolutely no difference, since I'm never going to divide temperatures.

It doesn't even matter much for meters and kilometers, since I very rarely need to talk about things that are kilometers away and meters away in the same context. It's handy to have sane units for those, though, since there you can multiply and divide in your calculations.

Temperature arguments never seemed particularly compelling to me. They assume 100 is more convenient, which I find wrong, since you're usually talking about 102, 86, 95, etc anyway.

> increased granularity (nobody would use half °C in practice)

We use 0.1°C for even better granularity. E.g. weather sites, all my digital thermometers, etc.

> when was the last time you saw 100°C written on a device?

Daily. Ovens in Europe typically will have a temperature range that's something like 50-400 C. I've never seen oven without a 100 C setting. Sauna thermometers will typically go from ~20 degrees to either 120 or 140 Celsius.

> The main niceties are the increased granularity (nobody would use half °C in practice)

One decimal place is commonly used.