Tuesday, February 23, 2021

Units

I went down a rabbit hole trying to figure out where a "stone" came from. British units seem to combine elegant binary simplicity with random lunacy. It turns out that a stone was even weirder than I thought: not just 14 pounds when talking about people's weight, but 8 pounds for meat (the 6 pound difference from 14 pounds for live weight was assumed to be the butcher's share), 12 pounds for lead, 8 pounds for spices, and 5 pounds for glass. "in practice varied according to local standards" It's easy to think of England as a single country--this is a sharp reminder that it wasn't so for a long time. And, of course, there's no guarantee it will stay a single country forever.

So of course that leads to money and the Charlemagne system that the Brits used until 1971: 240 denarius to a silver pound (1 solidus = 12 denari). Charlemagne's denarius would be about \$1.30 worth of silver--and recalling that the daily income for much of the world has been O(\$2/day), the New Testament denarius = day's wage fits right in. (His silver pound was about 3/4 of our pound.) So what's with the guinea, ringing in at 1 pound and 1 shilling? It looks like that was an artifact of trying to maintain both a silver and a gold standard simultaneously. They started out the same, but the price of gold went up, and after a while they fixed it back down to the current standard of a pound and a shilling. Gold was more high-toned than silver, so even after the coins weren't made anymore prices for high-toned stuff was in guineas.

Lengths are goofy. 3 barleycorns to the inch, 12 inches to the foot, 3 feet to the yard {looks like we're doing 3's instead of powers of 2 but it isn't crazy yet}, 16.5 feet to the rod {what??}, 320 rods to the mile {at least it's a round number}, 5280 feet to the mile {who can remember that?}.

16 ounces to the pound {nicely binary}, 14 pounds to a stone {??}, 8 stone to the hundredweight {but it isn't a hundred anything!}, 20 hundredweight in a long ton {2240 pounds}. There's lots of fossil history broken up and and jammed together in that head cheese of a system.

2 comments:

Assistant Village Idiot said...

I have always been fascinated by the same.

You haven't mentioned anything like the worst of it here, but you must have seen it looking things up. Horses are measured in hands, perches are a further measure of length, and we still use pints, quarts, and gallons, which are based on...we don't know. A Latin word for bucket, seemingly, and all different sizes - a corn gallon, and ale gallon, a wine gallon.
Acres, ells and cubits, terces. That 16.5 feet in a rod comes from all the units of measure being redefined upward by 11/10 for some reason I forget. It had been a more-understandable 15 feet before that.

james said...

I love fluid ounces, cups, pints, quarts, and gallons, though. The base is arbitrary, but it's so wonderfully binary and computer-ready...