The OG metric system (from the XVIII century) had no prefix for 10⁶. “Mega-” would be only formally acknowledged by the SI in 1960.
The ton units (yup, plural) backtrack all the way to a volume unit from the Middle Ages, the amount of liquid that you’d be able to put in a big arse cask*
Based on those two things, I think that the ton was standardised to 10⁶g considerably before the name “megagram” had the chance to appear, to the point that it became the default name across languages.
*I don’t know the English name for the cask [EDIT: “tun” acc. to @theplanlessman@feddit.uk ], but in Portuguese it’s “tonel”. From that “tonelada” (the unit). It used to be 800kg before the metric system though.
Yup - at least in Europe this backtracks all the way into the Middle Ages. And it was actually a big deal because the units were similar, neither completely identical nor completely different. And that was actually a big deal because people could argue which of those units they meant, specially when buying/selling stuff. (For example, let’s say that some Portuguese merchant agrees to sell “five tons of fish” to a random Englishman. Now you get:
the merchant arguing “five Portuguese tons”, expecting to sell 793*5=3965kg of fish
the buyer arguing “five English tons”, expecting to buy 1088*5=5440kg of fish
even if both were in good faith they’d feel themselves cheated on the deal.
To make it worse sometimes the units changed inside the same realm, over time.
Two relevant details:
Based on those two things, I think that the ton was standardised to 10⁶g considerably before the name “megagram” had the chance to appear, to the point that it became the default name across languages.
*I don’t know the English name for the cask [EDIT: “tun” acc. to @theplanlessman@feddit.uk ], but in Portuguese it’s “tonel”. From that “tonelada” (the unit). It used to be 800kg before the metric system though.
FYI the English name of that cask is “tun”.
Thanks for the info. (To be honest I couldn’t be bothered to look for it.)
What units did Portugal use before metric?
I’m from Brazil but I think that the units were the same anyway. The ones that I recall are (note: approximated values)
I don’t recall the volume units, but I don’t expect them to be too different from the anglo units.
Oh interesting. I didn’t know each country had its own slightly different version of imperial units
Yup - at least in Europe this backtracks all the way into the Middle Ages. And it was actually a big deal because the units were similar, neither completely identical nor completely different. And that was actually a big deal because people could argue which of those units they meant, specially when buying/selling stuff. (For example, let’s say that some Portuguese merchant agrees to sell “five tons of fish” to a random Englishman. Now you get:
even if both were in good faith they’d feel themselves cheated on the deal.
To make it worse sometimes the units changed inside the same realm, over time.
Oh, you are in for a surprise.
Just look at the imperial area measurement unities. Very few countries standardized them, and even on those, people don’t really use the standard.