in mechanics, a machine that is moved by clock-work. See Watch.

Perpetual Movement. Some have attempted to find a perpetual movement, but without success; and there is reason to think, from the principles of mechanics, that such a movement is impossible: for though in many cases of bodies acting upon one another, there is a gain of absolute motion; yet the gain is always equal in opposite directions, so that the quantity of direct motion is never increased.

To make a perpetual movement it appears necessary, that a certain system of bodies, of a determined number and quantity, should move in a certain space forever, and in a certain way and manner: and for this there must be a series of actions returning in a circle, otherwise the movement will not be perpetual; so that any action by which the absolute quantity of force is increased, of which there are several sorts, must have its corresponding counter-action, by which the gain of force is destroyed, and the quantity of force restored to its first state.

Thus, by these actions, there will never be any gain of direct force, to overcome the friction and the resistance of the medium; so that every motion being diminished by these resistances, they must at length languish and cease.

**Mould**, or **Mold**, in the mechanic arts, &c., a cavity cut with a design to give its form or impression to some softer matter applied therein, of great use in sculpture, foundry, &c.

**Mould**, in agriculture, a loose kind of earth, everywhere obvious on the surface of the ground, called also natural or mother earth; by some also loam.

**Mouldiness**, a term applied to bodies which corrupt in the air, from some hidden principle of humidity therein; and whose corruption shews itself by a certain white down, or lanugo, on their surface, which, viewed through a microscope, appears like a kind of meadow, out of which arise herbs and flowers, some only in the bud, others full blown, and others decayed, each having its root, stalk, and other parts.

**Moulding**, anything cast in a mould, or that seems to have been so, though in reality it were cut with a chisel, or the ax.

**Mouldings**, in architecture, projections beyond the naked wall, column, wainscot, &c., the assemblage of which forms cornices, door-cases, and other decorations of architecture. See **Architecture**.

**Moulinet**, is used, in mechanics, to signify a roller, which being crossed with two levers, is usually applied to cranes, capstans, and other sorts of engines of the like nature, to draw ropes, and heave up stones, &c.

**Moulinet** is also a kind of turnstile, or wooden cross, which turns horizontally upon a stake fixed in the ground; usually placed in passages to keep out horses, and to oblige passengers to go and come one by one. These moulinets are often set near the outworks of fortified places at the sides of the barriers, through which people pass on foot.

**Mound**, a term used for a bank or rampart, or other fence, particularly that of earth.

**Mound**, in heraldry, a ball or globe with a cross upon it, such as our kings are usually drawn with, holding it in their left hand, as they do the sceptre in the right.

**Mount**, an elevation of earth, called also mountain. See **Mountain**.

**Mount St Michael**, a borough-town of Cornwall, situated on a bay of the English channel, called Mounts Bay, eighteen miles west of Falmouth.

It sends two members to parliament.

**Mount Sorrel**, a market town of Leicestershire, seven miles north of Leicester.

**Mount of Piety**, certain funds or establishments in Italy, where money is lent out, on some small security. We had also mounts of piety in England, raised by contribution for the benefit of people ruined by the extortions of the Jews.

**Mountain**, a part of the earth, rising to a considerable height above the level of the surface thereof.

**Mouse**, in zoology. See **Mus**.

**Mouse-ear**, in botany. See **Hierachium**.

**Mouse-tail**. See **Myosurus**.

**Dar Mouse**. See **Sorex**.

**Sea-Mouse**. See **Aphrodita**.

**Mouzel**, or **Mosul**, a city of Asiatic Turkey, in the province of Diarbek, or Mesopotamia, situated on the river Tigris, opposite the place where Nineveh stood; E. long. 43°, and N. lat. 36°.

**Mouth**, in anatomy. See **Anatomy**, p. 299.

**Mouth** is used in the courts of princes, for what relates to their eating and drinking: Hence officers of the mouth, yeomen of the mouth.