DECHEN, ERNST HEINRICH KARL VON (1800-1889), German geologist, was born in Berlin on the 25th of March 1800, and was educated in the university in that city. He subsequently studied mining in Bochum and Essen, and was in 1820 placed in the mining department of the Prussian state, serving on the staff until 1864, and becoming director in 1841 when he was stationed at Bonn. In early years he made journeys to study the mining systems of other countries, and with this object he visited England and Scotland in company with Karl von Oeynhausen (1797-1865). In the course of his work he paid special attention to the coal-formation of Westphalia and northern Europe generally, and he greatly furthered the progress made in mining and metallurgical works in Rhenish Prussia. He made numerous contributions to geological literature; notably the following:—Geognostische Umrisse der Rheinländer zwischen Basel und Mainz mit besonderer Rücksicht auf das Vorkommen des Steinsalzes (with von Oeynhausen and La Roche), 2 vols. (Berlin, 1825); Geognostische Führer in das Siebengebirge am Rhein (Bonn, 1861); Die nutzbaren Mineralien und Gebirgsarten im deutschen Reiche (1873). But his main work was a geological map of Rhenish Prussia and Westphalia in 35 sheets on the scale of 1 : 80,000, issued with two volumes of explanatory text (1855-1882). He published also a small geological map of Germany (1869). He died at Bonn on the 15th of February 1889.
(H. B. W.)
DECIDUOUS (from Lat. decidere, to fall down), a botanical and zoological term for “falling in season,” as of petals after flowering, leaves in autumn, the teeth or horns of animals, or the wings of insects.
DECIMAL COINAGE.[1] 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, is a decimal system. Thus if the standard unit be 1 the higher coins will be 10, 100, 1000, &c., the lower .1, .01, .001, &c. 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 standard unit—the franc—has the 10 franc and the 100 franc pieces above it; the 10 centime below it; there are also, however, 50 franc, 20 franc, 5 franc, 2 franc pieces as well as 50 and 20 centime ones. Similar irregularities occur in the German and United States coinages, and indeed in all countries in which a decimal system has been established. Popular convenience has compelled this departure from the strict decimal form.
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) with the dollar as the unit, and France soon followed (1799 and 1803), her system being extended to the countries of the Latin Union (1865). The German empire (1873), the Scandinavian States (1875), Austria-Hungary (1870, developed in 1892) and Russia (1839 and 1897) are further adherents to the decimal system. The Latin-American countries and Japan (1871) have also adopted it.
In England proposals for decimalizing the coinage have long been under discussion at intervals. Besides the inconvenience of altering the established currency, the difficulty of choosing between the different schemes propounded has been a considerable obstacle. One plan took the farthing as a base: then 10 farthings = 1 doit (2½d.), 10 doits = 1 florin (2s. 1d.), 10 florins = 1 pound (20s. 10d.). The advantages claimed for this scheme were (1) the preservation of the smaller coins (the penny = 4 farthings); and (2) the avoidance of interference with the smaller retail prices. Its great disadvantage was the destruction of the existing unit of value—the pound—and the consequent disturbance of all accounts. A second proposal would retain the pound as unit and the florin, but would subdivide the latter into 100 “units” (or farthings reduced 4%) and introduce a new coin = 10 units (2.4d.). By it the unit of account would remain as at present, and the shilling (as 50 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 establishment 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 10 francs or (by an anticipated reduction of the dollar) 2 dollars. None of these plans has gained any great amount of popular support.
For the general question of monetary scales see [Money], and for the decimal system in reference to weights and measures see [Metric System] and [Weights and Measures].
(C. F. B.)