Dollar has more silver, as to why it has more silver than the equivalent of smaller denominations will have to be answered by someone else.
10c - .07234 x 10 = 0.7234oz. 25c - .18084 x 4 = 0.72336oz. 50c - .36169 x 2 = 0.72338oz. $1 - .77344oz. I do remember reading, somewhere, an explanation for this disparity, but I've forgotten where. Chris
I am not positive, but I think it had something to do with being closer to par with the Mexico 8 Reales at 0.7980 and other trade dollars at the time.
The monarchs of every nation had since the first coins decided what the weight and fineness of each denomination of their coinage would be. And those numbers were always subject to change at any time that the monarch chose to change them. If the crown needed money to pay for wars or to pay debts then the fineness and/or weight would go down for a time. This would increase seigniorage and thus the funds in the treasury. But it was pretty much standard practice among all nations that the lower denomination coinage had less pure silver (percentage wise) in each coin than the next higher denomination coin, with the highest denomination having the highest percentage of pure silver. In other words one 8 reales coin had more silver in it than eight 1 reale coins, and so on. The US wanted to be a bit different to set themselves apart from other nations and thus decided to make all lower denominations basically equal in silver content and the highest denomination only slightly higher. This was done to instill confidence in the currency of the new, and as yet unknown, nation. Confidence in your currency is the one thing that every nation needed if the nation was to survive because since the dawn of time trade was what made the world go round. And without confidence in your currency there would be little trade.
The Coinage Act of 1792 specified that he dollar, half dollar and quarter all be in perfect ratio with one another for the amount of silver they contained. The dime was slightly less and the half-dime even more. It was likely with the change in silver weights in the 1850s that these ratios started to change.
After the silver dollar was not included among "authorized coins" in the Coinage Act of 1873, the "free silver" lobby managed to pass an authorization act (the Bland-Allison Act) in 1878. President Hayes vetoed the bill, but Congress overrode his veto, and the minting of silver dollars commenced at a rapid rate. As you might guess, miners and farmers strongly supported the minting of silver dollars in preference to gold. There's an excellent article at: http://en.wikipedia.org/wiki/Bland-allison_act
I stand corrected, it wasn't until later years when the silver ratio changed for the quarter and half as compared to the dollar.
