Your Thoughts On Why The US Mint Made Coins Of 90% Silver Not Sterling

So the question becomes why did the Spanish use .900 silver. I think that discouraging melting is a good reason.

I think you guys might be right, however why would Britain and the entire Commonwealth (including Canada to the North) all use Sterling Silver (Canada up till 1919)?

You would imagine that if melting was an issue for sure Britain would see that as well.

I think the hypothesis that it based off the 8 reales is the most plausible. According to this article written by R.W. Julian, there was a plan in 1783 to set the fineness close to the sterling standard but it fell through because it did not consider the widespread use of Spanish colonial coinage. There were people like Thomas Jefferson who felt that our dollar had to correspond to the Spanish 8 reales. After much tinkering, the fineness was set in 1792 at 0.8924 which is not that far off the 0.896 fineness of contemporary 8 reales. According to the article, it was the U.S mint assayer Albion Coxe who suggested that they secretly mint coins to 0.900 fineness in order to make the calculations and refining easier. My guess is that may be why the standard was officially changed to 90% in the 1830's.

According to wikipedia, the fineness was originally set at 0.9305 in 1497 but debased to 0.9166 in 1728, secretly to 0.903 in 1772, and again secretly to 0.896 in 1786. I am not totally sure the reasons were the same for the 1728 and 1786 debasements but in this article written by Daniel Sedwick, the reason in 1772 was "to alleviate Spain's mounting financial chaos."

I don't know if this is fact but it seems to me that when countries get into financial problems, they usually try to create more money. When you are on a bimetallic standard, the way you "print money" is by reducing the weight and fineness of coinage. Reducing the fineness would probably be preferable to reducing the weight since it is harder to detect.

In the documents I've been transcribing for RWB there are documents discussing the change of fineness from .8924 to .900 and one of the major points that was stressed was ease of calculations and reduced chances of error in the calculations.

Very interesting.

Even with the Philly mint working around the clock and technological advances in minting, there were not nearly enough coins to supply the nation, especially as the frontier steadily grew westward. A fineness of near .900 was enough to be competitive with European silver crowns (e.g. Thalers & 8 Reales) but allowed for Mint seigniorage and made the calculation of coin weights and proportions mathematically easier. The American dollar contained less silver than a full-weight Spanish 8 Reales, by 1-1.5 grams.

Unfortunately for the Government, "good" silver that entered circulation was mostly hoarded by banks and merchants; the result was that most of the circulating foreign silver was underweight - debased, heavily worn, clipped, filed, or otherwise devalued. This made it difficult to establish the Federal coinage as the de facto money supply since, by Jefferson's 1806 law, the foreign specie retained nominal parity with its Federal counterparts, despite the "actual" silver value of the foreign specie being less than its face value in most cases. This problem would not be meaningfully addressed for another 50+ years.

I agree that the most likely reason for (approximately) .900 silver was due to the ease of calculation and composition. I would also add that the use of .925 silver would have been disastrous; any such coins would have rapidly fled the country and been replaced by debased foreign silver, and the operation of the Mint would not have been sustainable. The .925 British coinage was already nearly nonexistent in circulation by the start of the 19th c. and had been for 30+ years before that; it tended to flow back to Britain and stay there.

While I agree with the above reasons, coins back them were made to circulate and I believe that this was the main reason... 90% holds up better to wear and tear...