Dollar, the monetary unit in the United States and several other countries, both of coined money and money of account. All values in the United States are expressed in dollars and cents, or hundredths. The term mill, for the 1/1000 of a dollar, is rarely employed. The dollar unit, as a money of account, was established by act of congress of April 2, 1792, and the same act provides for the coinage of a silver dollar " of the value of a Spanish milled dollar as the same is now current," and of half and quarter dollars in proportion. The silver dollar was first coined in 1794, weighing 416 grains, of which 37l 1/4 grains were pure silver, the fineness being 892.4 thousandths. The act of Jan. 18, 1837, reduces the standard weight to 412 1/2 grains, but increases the fineness to 900 thousandths, the quantity of pure silver remaining 371 1/4 grains as before, and the half and quarter dollars suffering proportional changes. By the act of Feb. 21, 1853, the half dollar was reduced in weight to 192 grains, and the quarter dollar in proportion, and these coins became a legal tender only for sums not exceeding $5, while the dollar suffered no change in weight, and remained a legal tender for all sums. The act of March 3, 1849, directs a coinage of gold dollars.

They were issued the same year, weighing 25 8/10 grains, 9/10 fine, 23 22/100 grains being pure gold. By the act of Feb. 21, 1853, the three-dollar piece of gold was authorized, 9/10 fine and weighing 77.4 grains. The act of Feb. 12, 1873, known as the "coinage act of 1873," makes the gold dollar the unit of value, but effects no change in the weight or fineness of that coin or of the three-dollar piece, which continues to be a legal tender for all sums. By this act, however, a " trade dollar," weighing 420 grains, designed for the convenience of commerce with China and Japan, was substituted for the old silver dollar, while the weight of the half dollar was fixed at 12 grams, or 192.9 grains, half the weight of the five-franc piece of France and other European countries, the quarter dollar being proportional. The fineness of these coins is unchanged, but the silver dollar is no longer a legal tender for sums exceeding $5. The number of coins of each kind produced at the mint and its branches, from their organization to June 30, 1872, is as follows:

Three-dollar pieces..............

....... 390,971

One-dollar places (gold)....

....... 19.015.642

One-dollar places(silver)...

....... 8.045.883

Half-dollar places.........

....... 199.630.871

Quater-dollar places.........

....... 87,586,274

Whole number of pieces.......

314,619,596

The value of the coinage is $149,933,897. - The term dollar is of German origin. During the years 1517 - '2(5 the counts Schlick, under a right of mintage conferred by the emperor Sigismund in 1437 upon their house, caused to be struck a series of silver coins of 1 oz. weight, and worth about 113 cents of our money. These pieces were coined at Joachimsthal (Joachim's dale), a mining town of Bohemia, and came to be known in circulation as Joachimsthaler, and then for shortness Thaler; and this name for coins and money of account has been widely used in the German states ever since. Some German scholars, however, derive the term Thaler from talent, which in the middle ages designated a pound of gold. In Norway and Sweden we find the daler, and in Spain the dalera, the Spanish dollar which for centuries figured so conspicuously in the commerce of the world. It was the Spanish pillar dollar (called also the milled dollar from its milled edge) that was taken as the basis of the United States coinage and money of account. By the act of April 2, 1792, 37l 1/4 grains of pure silver and 24 3/4 grains of pure gold were declared to be equivalent one to the other, and to the dollar of account. At that time, as now in Great Britain, 113 grains of pure gold were the equivalent of the pound sterling.

The value of £1 in federal money, therefore, was $4 56.5. Prior to this date, and during the confederation, the dollar of account, as compared with sterling currency, had been rated at 4s. 6d., which was an exaggerated valuation of the Spanish dollar; and in accordance with this valuation the congress of the confederation had established $4 44.4 as the custom house value of the pound sterling. The effect of the act of 1792 was really to reduce the value of our dollar of account, but apparently to increase the value of the pound sterling about 2| per cent. By the act of June 28, 1834, the weight of fine gold to the dollar was reduced from 24.75 to 23.20 grains; and on Jan. 18, 1837, it was fixed at 23.22 grains. Comparing this latter weight with the pound sterling of 113 grains, we find an apparent increase in the value of £1 to $4 86.6, an advance of exactly 9 1/2 per cent. upon the old valuation of $4 44.4. We have here the explanation of the practice of quoting sterling exchange at 9 1/2 per cent. premium when it is really at par. A much more intelligible method would be to state in dollars and cents the ruling rate per pound sterling for bills on London; e. g.: $4 84, $4 87, $4 90, etc. - Spanish dollars were chiefly coined in the Spanish American colonies.

The best known variety was the pillar dollar, so called from the two pillars on its reverse, representing the "Pillars of Hercules," the ancient name of the opposite promontories at the straits of Gibraltar. The rude imitation of these pillars in writing, connecting them by a scroll, is said to have been the origin of the dollar mark ($). Another explanation is that, as the dollar consisted of 8 reals (8 R. being stamped upon it), the mark was designed to stand for the "piece of eight," as the dollar was commonly called, the two vertical lines being employed to distinguish it from the figure 8. The Spanish American dollars ceased to be coined when the colonies became independent, and since 1822 their place in commerce has been supplied by the dollars of Mexico, Bolivia, and Peru. (See Coins.)