From Trailing the Giant Panda by Theodore Roosevelt and Kermit Roosevelt, published in 1929 Here we stopped to arrange our money transfers. This is a most complicated matter as the different denominations, though ostensibly dealing in the same medium, the cent, have entirely different relative values. The standard, of course, is the dollar "Mex", worth about fifty cents of our money. The half-dollar piece is the most valuable, -- the paper dollar the least. One dollar in half-dollar silver pieces is worth many dollars in paper. The twenty-cent pieces stand in between. It takes some 120 cents in them to equal 100 cents in the half-dollars. This is because certain enterprising officials had them coined in brass outside of the country. To make matters worse, the values are different in most places and in certain districts paper and small coin are not accepted at all. The final straw is added by the practice of separate coinage for the different provinces. Making out an income tax in America is simple compared with figuring exchange in China. The "half-dollar piece" he refers to is a silver dollar sized coin, either Mexican or Chinese. When the US changed to the gold standard, the Chinese "Mex" silver dollar was pegged at half a "gold" dollar. China Dollar 1914 Yuan Shih-kai "Fat Man" type (Silver, 38mm, 26.62gm)