DECIMAL COINAGE, any currency in which the various denominations of coin are arranged in multiples or submultiples of ten (Lat. decem) with reference to a standard unit. Thus if the standard unit be 1 the higher coins will be io, I oo, i,000, etc., the lower •1, •oi, •001, etc. In a perfect system there would be no breaks or interpolations, but the actual currencies described as "decimal" do not show this rigid symmetry. In France the stand ard unit—the franc—has the io franc and the ioo franc pieces above it ; the io centime below it ; there are also, however, 5o franc, 20 franc, 5 franc, 2 franc pieces as well as 5o and 20 cen time and other denominations. Similar irregularities occur in the German and United States coinages.
Subject to these practical modifications the leading countries of the world (Great Britain and India are the chief exceptions) have adopted decimal coinage. The United States led the way (1786 and 1792; see MORRIS, GOUVERNEUR), and France soon followed (1799 and 1803), her system being extended to the countries of the Latin Union (1865) . Germany (1873), the Scan dinavian States (1875), Austria-Hungary (187o, developed in I 89 2) and Russia (1839 and 1897) are further adherents to the decimal system. The Latin-American countries and Japan (1871) have also adopted it.
In Great Britain proposals for decimalizing the coinage have often been discussed. Besides the inconvenience of altering the established currency, the difficulty of choosing between the differ ent schemes propounded has been a considerable obstacle. One plan took the farthing as a base: then 1 o farthings = I doit (2 d.) , io doits = i florin (2s. id.), 1 o florins = i pound (2os. i od.) . The advantages claimed for this scheme were the preserva tion of the smaller coins and the avoidance of interference with the smaller retail prices. Its great disadvantage was the destruc tion of the existing unit of value. Another proposal would retain the pound as unit and the florin, but would subdivide the latter into too "units" (or farthings reduced 4%) and introduce a new coin= 1 o units (2.4d.) . By it the unit of account would remain as at present, and the shilling (as 5o units) would continue in use. The alteration of the bronze and several silver coins, and the need of readjusting all values and prices expressed in pence, formed the principal difficulties.
A third scheme, which was connected with the assimilation of English to French and American money, proposed the establish ment of an 8s. gold coin as unit, with the tenpenny or franc and the penny (reduced by 4%) as subdivisions. The new coin would be equivalent to i o francs or (by an anticipated reduction of the dollar) 2 dollars.
A fourth scheme was put forward by the Decimal Association to meet the objections raised by the Royal Commission on Coin age of 1918-2o to the proposed £-mill system (= f divided into 1,00o parts). This scheme left all the silver coins unchanged but proposed to increase the value of the copper coins by 2o%, so that the shilling would consist of ten instead of 12 pence.
For the general question of monetary scales see MONEY, and for the decimal system in reference to weights and measures see METRIC SYSTEM and MEASURES AND WEIGHTS. (C. F. B.)