developed as the need for a universal system became more and more imperative. Abb Gabriel Mouton in 1670 proposed an aliquot part of the circumference of the earth as an international unit of length. Other authorities, including Picard, La Condamine, Jefferson and Taileyrand, favored the length of a pendulum beating seconds. A committee of the French Academy of Sciences, which was appointed in 1790 and included Laplace, Condorcet, Borda, Lagrange and Monge, reported in favor of the tenth-millionth part of a quarter of a terrestrial meridian or the distance from the equator to the North Pole as the standard unit of length. The success of the decimal money-system of the United States appears to have won many advocates for the metric system of weights and measures. The unit recommended by the committee of 1790 was established by decree; and the nomenclature was legally fixed by a law of 1795; but the metric system had still to secure adherents among the masses and abroad. This was effected by the adoption of the report of an international commission in 1799. Standard units were deposited in the Paris archives; and by 1837 the use of the metric system was made compulsory in France in all departments. In i860 the metric system was recognized by law in the United States. Several attempts have been made to render it obligatory; but it has seemed preferable to allow the system to win its way for a time, as it is doing, on its own merits.

The unit of length is a metre; the unit of weight a gram; the unit of capacity a litre. The equivalent of a metre is 39.37079 inches; of a gram, 15.43235 grains; of a litre 61.02705 cubic inches. A gram has the weight of one cubic centimetre; a litre the volume of one cubic decimetre. Prefixes are used to indicate submultiples and multiples of the units, thus:

Milli —one thousandth part.

Centi —one hundredth part.

Deci —one tenth part.

Deca —ten times.

Hecto—one hundred times.

Kilo —one thousand times.

So a centimetre is the hundredth of a metre, a decimetre the tenth of a metre, a kilogram one thousand grams, and so on. The labor of the calculations and reductions in terms of weights and measures is reduced to a minimum by the simple relation between the units of mass and dimension and by the use of decimal parts and decimal notation. Metres and kilograms constructed of an alloy of iridium and platinum are furnished to countries which need them from the Observatory of the International Bureau, established at St. Cloud in 1878.

Metronome (mĕt'r-nōm), an instrument for dividing or "beating" time, used chiefly in the study of music. As ordinarily constructed, it looks like an inverted pendulum

swaying before a pyramid, the pendulum being moved by clockwork and the motion retarded or accelerated by sliding up or down a metal weight appended to the wire. If this weight be near the point of suspension, the motion will be rapid; if near the top, correspondingly slow.

Metternich (mĕt'tr-nĭk), Clemens Wen= zel Nepomuk Lothar, Prince, an Austrian statesman, was born at Coblentz, Prussia, May 15, 1773. He studied at Strassburg and Mainz (Mayence). He was appointed Austrian minister to Dresden when he was 28, and two years later became ambassador to Berlin. After the peace of Presburg he was sent as minister to the court of Napoleon. He concluded the treaty of Fontainebleau in 1807, and in 1809 became minister of foreign affairs. He was made a prince of the empire in 1813, and in 1821 became chancellor. The Revolution of 1848, was felt at Vienna, and Metternich was compelled to flee to England. After his return he took no part in public affairs, and died at Vienna, June 11, 1859. In 1880-84 his Memoirs were published. See Metternich, by Malleson, in the Statesmen Series.

Metz (mets), the capital and strongest fortified town of Lorraine, Germany, on Moselle River. It has a series of forts around it, which have been strengthened since the annexation to Germany (1871). The making of saddles and shoes and tanning are its manufactures; and the trade is largely in wine, brandy and preserved fruits. In 1552 it was taken by the French, to whom it was formally ceded in 1648. In the Franco-Prussian War it was occupied by Bazaine, who, after a long siege, surrendered it to the German army, and by the treaty of Frankfort it became a German city. Population 60,396.

Meuse (mz), a river which rises in France, and flows north to Belgium and into Holland. Turning to the west, it joins the Waal, one of the mouths of the Rhine, and becomes the Maas. Rotterdam stands on the New Maas. The river is 500 miles long.

Mexico (mek'si-ko), a city, the capital of the Republic of Mexico, is situated in the midst of the central tableland of the country, 7,347 feet above the sea. It is known in history as the capital of the Monte-zumas, founded by the Aztecs about 1325. The city was in its full glory when Cortez conquered it in 1521, destroying a large part of the ancient town. He rebuilt it on its present plan, using a company of 400,000 Indians in the work. It was occupied by the Spaniards for 300 years, and has been the scene of revolution and the battlefield for contending armies. It to-day is a modern city in every sense of the word ; the political, social, industrial and financial center of the republic, and with its suburbs has a population of 500,000. The principal streets are broad and well-paved; the city is electrically