History ? - Why did a silver dime weigh 2.5 grams - Was the Mint metric?

jp297

A while back, learned here how the ratio of the weights of US 90% silver dimes, quarters, and halves, parallel the value.

But recently wondered why they seem so close to "even" gram weights (ex. 2.5g dime) rather than oz weights (ex. the av. oz 0.08818 / tr. oz 0.08037 - dime)?

Was the mint metric? Or is it simply that gram measurements are so much smaller units that things are rounded that way? Or was the dime historically close to 2.5g (or the dollar to 25g) and some, um, very particular entity made it exact?

Sorry. This newbie gets historical curiosity occasionally. Thanks.

giorgio11

The Mint went to even metric weights in 1873 for the Arrows dimes, it was a laughably small increase from the previous weight (0.01 gm, 2.49 gm vs 2.5 gm). It was part of a big push to go metric that never caught on despite the efforts of Rep. John A. Kasson and others.

Here are some discussions about it that are relevant to the subject, from the Heritage archives.

1879 Flowing Hair stella-Heritage

Another Stella

1874 Arrows Dime-Metric Weight

bronco2078

All the fractional coins wound up being 25 grams of 90% silver = 1 dollar of face value. 25 grams of 90% silver is also the size of the 5 franc sized coins of the countries in the latin monetary union. The .0723 troy ounce dime is identical to the .0723 troy ounce 50 centimes coin of france or the half franc of switzerland of the 1850's . somewhere in the 1850's they devalued to .835 fineness on the smaller coins but the 5 franc coins stayed at 25 grams of 90% silver.

CaptHenway

<< <i>A while back, learned here how the ratio of the weights of US 90% silver dimes, quarters, and halves, parallel the value.

But recently wondered why they seem so close to "even" gram weights (ex. 2.5g dime) rather than oz weights (ex. the av. oz 0.08818 / tr. oz 0.08037 - dime)?

Was the mint metric? Or is it simply that gram measurements are so much smaller units that things are rounded that way? Or was the dime historically close to 2.5g (or the dollar to 25g) and some, um, very particular entity made it exact?

Sorry. This newbie gets historical curiosity occasionally. Thanks. >>



The weights of the fractional silver coins were reduced by about 7% from previous standards in 1853. By coincidence this made the new weights close to round fractional gram weights.

Subsequent to that, the Latin Monetary Union was founded with round gram weights that had the Half Franc at 2.5 grams, very close to the dime. Because silver was cheap, the U.S. decided to round our fractional silver up a tiny bit. In 1875 we added a 5 gram 20 cent piece because that was the weight of the Franc.

TD

ProofArtworkonCircs

With clad coinage the US mint went to the pound standard. One pound equals $20.
The US 5 cents weighs 5 grams. In the meantime metric Canada uses 100 5 cent pieces to the pound (dating back to the pre metric period).

jp297

Wow. Fascinating historical stuff. Lots of starting points for more learning.
Thanks very much to all.

ranshdow

Also- the 0.48375 troy oz. of pure gold in an 1838-1933 $10 gold eagle is almost exactly 15g. (15.04g)

CaptHenway

And the Mexican gold coins struck for the past century or so, (in restrike form since 1959), have the 20 Pesos containing an even 15.0 grams of pure gold, the other coins being proportional to that.