What is a “dollar”? Law and history reveals what it is.
The US Constitution uses the word “dollar” in 2 separate places. In Art. 1, § 9, the Constitution mentions a tax on slaves not to exceed “ten dollars for each Person.” The 7th Amendment provides that jury trials are “preserved” when “the value in controversy shall exceed twenty dollars”. Words in the constitution mean whatever they meant when the constitution was adopted. “The Constitution is a written instrument. As such, its meaning does not alter. That which it meant when it was adopted, it means now.” See South Carolina v. United States, 199 US 437, 448 (1905), posted here:
In April, 1786, the Continental Congress proposed that the “dollar” be the “money of account of the United States”. See attached pages from the Journals. The “dollar” then in common circulation in this country was the “Spanish milled silver dollar”.
Thus we know that just prior to the adoption of the Constitution, “the money of account of the US” or “dollar” was the then current Spanish milled silver dollar.
When the Constitution was adopted, the legal tender power of the States via Art. 1, §10, cl. 1 was limited to gold and silver, and that gold and silver was simply to be “coined” by a mint operated by the US Govt. See Art. 1, §8, cl. 5 (“to coin money, regulate the value thereof”). The intent of the framers of the constitution was that our money, the dollar, be specie.
In 1792, Alex Hamilton determined by scientific method exactly what was a “dollar” then in circulation. He acquired 1000 Spanish milled silver dollars, melted them, and then determined the average weight of 1 dollar by dividing the total grains of pure silver in the melted mass by 1000. That weight was found to be 371.25 grains of pure silver. This finding was then memorialized in the Coinage Act of 1792, which is attached.
A “dollar” is a weight of silver being 371.25 grains of pure silver. This weight is about 0.77 of an ounce. An ounce of pure silver thus has a legal “dollar” value of $1.2929292929.