ROCROI, a small t. of France, in the dep. of Ardennes, 15 m. n.w. of Mezieres, is a fortress of the fourth class, and is situated in a fine, extensive plain, bounded on all sides by, the forest of Ardennes. Pop. '76, 1052. It is memorable for the victory gained by the great Conde (then duke of 'Enghien) over the Spaniards, May 19, 1643. The Spanish army was composed of veteran bands of Walloons, Spaniards, and Italians; and their general, Don Francisco de Mellos, the governor of the Low Countries, was a -commander worthy of his army. The French (22,000) were also good troops; but their general, Conde, was a young and inexperienced officer. At first the battle was unfavor able to the French, but at last the Spaniards were thrown-into irretrievable rout. The count of Fuentes, the commander of the redoubtable infantry, and 10,000 of his men, were among the slain; and 5,000 men, with all the cannon, many standards, and the baton of the count de Mellos, were captured. But, far beyond all material losses, the renown of invincibility, first acquired by the Spanish infantry on the field of Pavia (1525), and confirmed at St. Quentin, Gravelines, and Prague, was destroyed.
ROD, called also a pole, or linear perch, a measure of length of 5 yards, or 164- feet. The square rod, called generally a rood, is employed in estimating masonry, and contains 161 >< 16i, or 272} square feet.
gnawers), or RODENTS, in the system of Cuvier, an order of mam malia, almost exactly corresponding with the glires of Linngeus. The order is a truly natural one, and is therefore universally recognized by naturalists. The rodentia are small quadrupeds; the largest of them—the capybara—not being equal iu size to a hog, to this crder belong the smallest of mammalia. They are very numerous, and widely distributed over the globe, particularly abundant in South America, and rarest in Australia. They are all remarkably characterized by their front teeth, variously regarded as incisors and canines—the true incisors or canines being absent—which are large and of peculiar structure, two in each jaw, and separated by a considerable vacant interval from the molars. The front teeth have a plate of hard enamel in front, which wears more slowly than the substance of the rest of the tooth, so that being employed on hard substances, they acquire a chisel-like form, and unlike the teeth of mammals in general, they are always growing from a fresh pulp at the base, so that compensation is made for the wearing away at the tips; but when a tooth is accidentally destroyed, the opposite tooth continuing to grow, sometimes acquires a monstrous shape and size, from which cause rats and other rodents have been known to die, the enormous tooth preventing the eating of food, or even recurving and piercing the skull. , Tlie ordinary
food of most rodents consists of vegetable substances, and generally of a pretty hard kind, and their front teeth are adapted for comminuting it by gnawing, and are also used for gnawing wood, the shells of nuts, etc., in order to obtain access to food. The molar teeth haye flat crowns, having ridges of enamel, which make them more or less tuberculous; and these are iu the line of the jaw, while the only horizontal motion of which the lower jaw is capable is forward and backward, thus making the ridges of the molar teeth powerful instruments for the reduction of hard substances; the jaws also being in general very strong. In the rodents which eat only vegetable food, the molar teeth have rounded tubercles; while in the omnivorous kind—as rats—the tubereules become sharp points. The stomach is simple; the intestines are very long; the mourn is often large, sometimes larger than the stomach itself. The brain is not large, and is nearly smooth, and without convolutions; the rodents are not generally distinguished for sagacity, although some of them—as the beaver—exhibit remarkable instincts. Most of them may be easily tamed, but few of them seem capable of learning anything, and in general they merely acquire a familiarity with man. Of this the rabbit exhibits a very perfect example, although the rat seems to display a far higher intelligence. The eyes are directed laterally. The rodents very generally have the hinder limbs larger than the fore, and their motion is partly a kind of leaping. In some, this is as completely the case as in kangaroos. Some, as squirrels, have an admirable power of climbing trees; and a few, as beavers and water:voles, are aquatic. Most, if not all, have the habit of sitting on their haunches, and holding their food to their mouth by their fore paws; using both paws together, however, as the fore-feet have not at all the character of a hand. The thumb is never opposable to the other toes; sometimes it is rudimentary or wanting. The bones of the fore-leg are generally separate, but have not so much freedom of motion as in the The toes are 'terminated by claws. The pres ence or absence of clavicles (collar-bones) divides the order into two sections, to the first of which, having clavicles, belong squirrels, mice, rats, voles, the beaver, etc.; and to the second, without clavicles, belong porcupines, eavies, chinchillas, hares, rabbits, etc. The rodents are very numerous, about 400 species being known.