Velez-Malaga. A fortified town in the south of Spain, in the province of Malaga, 16 miles east from the city of that name. The town was taken from the Moors, by Ferdinand the Catholic, after a long siege.
Velish. A town of Russia in Europe, in the government of Vitepsk, situated on the Dwina. This place, which was founded by the Russians in 1536, was taken by the Poles in 1580, but in 1772 it again reverted to Russia.
Velites. In the Roman armies, the name of the light-armed troops, who were first instituted during the second Punic war, and were remarkable for their agility.
Velletri (anc. Velitræ). A town of the Papal States, in the Comarca, and 21 miles southeast from Rome. The ancient Velitræ was an important Volscian city destroyed by the Romans, but afterwards rebuilt. In 1734, Carlo Borbone, king of Naples, gained, near Velletri, a decisive victory over the Austrians, which secured the kingdom of the two Sicilies to the Spanish Bourbons.
Vellore. A town and fortress of British India, in the presidency of Madras, situated on the river Palar, 80 miles southwest from Madras. It is very strongly fortified. After the capture of Seringapatam, in 1799, Vellore was fixed on for the place of confinement or residence of the family of Tippoo Sahib. In July, 1806, a very serious mutiny took place among the garrison, composed principally of native troops. It was speedily suppressed by the gallant conduct of Col. Gillespie of the 19th Dragoons.
Velocimeter. An instrument for obtaining initial velocity, invented by Col. Benton, U. S. Ordnance Department. See [Chronoscope].
Velocity. Is rate of motion; the relation of motion to time, measured by the number of units of space passed over by the moving body in a unit of time, usually the number of feet in a second. The velocity of a projectile, at any point of its flight, is the space in feet passed over in a second of time, with a continuous, uniform motion. [Initial velocity] is the velocity at the muzzle of the piece; [remaining velocity] is the velocity at any point of the flight; terminal velocity is the velocity with which it strikes its object; and [final velocity] of descent in air, is the uniform velocity with which a projectile moves, when the resistance of the air becomes equal to the accelerating force of gravity. The initial velocity of a projectile may be determined by the principles of mechanics which govern the action of the powder, the resistance of the projectile, etc., or by direct experiment.
The instant that the charge of a fire-arm is converted into gas, it exerts an expansive effort which acts to drive the projectile out of the bore. If the gaseous mass be divided into elementary sections perpendicular to its length, it will be seen that, in their efforts to expand, each section has not only to overcome its own inertia, but the inertia of the piece and projectile, as well as the inertia of the sections which precede it. The tension of each section, therefore, increases from the extremities of the charge to some intermediate point where it is a maximum. The pressure on all sides of the section of maximum density being equal, it will remain at rest, while all the others will move in opposite directions, constantly pressing against the projectile and piece, and accelerating their velocities. As the projectile moves in the bore, the space in which the gases expand is increased, while their density is diminished; it follows that the force which sets a projectile in motion in a fire-arm varies from several causes: (1st) It varies as the space behind the projectile increases, or as the velocity regarded as a function of the time; (2d) It varies throughout the column of gas for the same instant of time; and (3d) It varies from the increasing quantities of gas developed in the successive instants of the combustion of the powder. See [Initial Velocity].
The motion of a body falling through the air will be accelerated by its weight, and retarded by the buoyant effort of the air, and the resistance which the air offers to motion. As the resistance of the air increases more rapidly than the velocity, it follows that there is a point where the retarding and accelerating forces will be equal, and that beyond this the body will move with a uniform velocity, equal to that which it had acquired down to this point. The buoyant effort of the air is equal to the weight of the volume displaced, or PdD; in which P is the weight and D the density of the projectile, and d the density of the air. When the projectile meets with a resistance equal to its weight, we shall have,
P (1 - dD) = ApR2v2 (1 + vr); (15)