Possible minor City & Guild errata

In City & Guild, page 140 under the 'Weights and Measures' section the weight of a pound is listed as 1/2,420 of a ton and at the bottom of the section is listed as 16 ounces = 1 pound = 1/2,420 ton.

Later on in the paragraph about ale and wine it list "A tun defines the weight of a ton" which is historically accurate. That ton would be what we call today the 'long ton' (compared to the short ton and metric ton) which is 2,240 lbs. At some point it seems that someone might have flipped the two middle digits.

While not affecting any mechanics and thus not an important edit, just clarification if this was an error or AM intentionally uses ahistorical weights would be appreciated.

[This is very minor and hopefully will not set off the frenzy that my other two recent errata threads have.]

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I think this is the difference between a "tun" and a "ton." I recently did a calculation based on this, and it looked right.

Historically a tun of ale/wine weighed a ton. The historical ton is the long ton, which weighs 2,240 lbs, and that is also the historical weight of a tun of ale/wine.

Correcting this number to a british ton would incidentally probably require recalculating every prices in that chapter.

A modern Imperial (American) Ton (2000 lbs) would be the weight of 250 gallons of water.
2240 lbs would be 280 gallons
2420 would be 302.5 gallons
the density of beer is slightly heavier than water, ranging from 1.004 (though that's an American beer and probably doesn't count) to 1.060 times the density of water. Unless you are including the weight of the container or not using gallons to measure the volume there really doesn't look like a god reason to have a ton come out to 2420 lbs.

According to Wikipedia the historical weight should be 2000 lbs
Ton - Wikipedia
at 256 Gallons it would come out to 2048 lbs.

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There is no Imperial American Units. There are Imperial Units and United States Customary Units.

Historically the closest system of units that would have been used during the start dates of Ars Magica is the Avoirdupois.

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If it says that (nobles parma) yes, there's a transposition there. The Mythic Tun is 2240 pounds.


Oh, ya, you’re right. I don’t know why I scaled up from a long ton to a ton. :frowning: Definitely looks like a transposition error.

If it was just a transposition error, then the prices are actually correct so no change.

It does say that and we talked about it a little in the Fan-Created Grimoire thread a few months ago but no one submitted it for errata. A thread yesterday brought it to my attention again. Easy fix.

Apparently not. Fixed, thank you.

But note that it is best to send errata directly to me (direct message on the forums), because I might not spot the threads.

So give you the choice if there is a possible frenzy or not. Will do.

Actually, not so much that. If there's a frenzy, it means that the issue is more complex than it might initially appear, and (at least from the long-term perspective) I'd like to know that in advance. I don't read all the threads on the forum, so I might miss one about errata, even if it has "errata" in the title. It's safer to send them directly to me, but it's fine to post on the forum first if you want to.

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I should have put a smiley or something on that post since it was meant as a joke. I'll make sure to shoot you a message with any further errata I find.

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The prices for gold and silver, for example, are directly derived from the 2,420. Whether the rest of the prices for goods table need to be reevaluated is a good question. To be frank, I've long played with the assumption that 2420 was picked to avoid choosing between the american and imperial weight systems. Much like the gallon isn't 1/240 tun in the imperial system either. In the UK, it's 1/252.

And now I have conflicting information on the extent of the errata…

The author says it was a typo, so I am going with that for the moment.