12 月英语四六级考试阅读提高练习(4)But, curiously, one of the rarest coins in the world is not made of gold, but of the relatively cheaper silver
In 1804, the United States mint( 造币厂) struck 19,570 silver dollars
That is what its records show
Today only six of this original number remain and these are unlikely ever to reach the auction market
So what happened to some 19,564 large silver coins, not the easiest sort of things to lose
One of the more romantic theories is that they were part of the payment to Napoleon for the American territory then known as Louisiana
But they never reached France
Somewhere in the Gulf of Mexico, the ship transporting them was sunk, either by a storm or by pirates (#£&)
The probable answer to the mystery is that they were melted down—since the silver value was greate