Informers. In the British service, were soldiers who gave information of false musters, or of pay illegally detained; and were, for said services, entitled to their discharge.
Ingauni. A Ligurian tribe who formerly inhabited the sea-coast and adjoining mountains at the foot of the Maritime Alps, on the west side of the Gulf of Genoa. They are mentioned as being engaged in hostilities with a neighboring tribe, the Epanterii, on the occasion of the landing of Mago, the brother of Hannibal, B.C. 205. They were several times engaged in wars with the Romans, but were finally defeated by the pro-consul, Æmilius Paullus, in a decisive engagement (losing 15,000 killed and 2500 prisoners), which resulted in their ultimate submission to the Roman sway.
Inglorious. Shameful; disgraceful; ignominious; as, he charged his troops with inglorious flight.
Inimical. Hostile.
Initial Velocity. In England the term muzzle velocity is frequently used. In gunnery, the initial velocity of a projectile is the velocity at the muzzle of the piece, and is determined by the use of the ballistic pendulum, the gun pendulum, the electro-ballistic machines, the Schultz chronoscope, or the Le Boulengé chronograph; the two last being now generally used in the U. S. service. The various plans in use differ only in the manner of recording and keeping the time of flight. The initial velocity of a shot may be ascertained by firing the gun, the axis being horizontal, at a target and measuring the distance of the point struck below the point where the axis of the gun produced would pierce the target. This is the vertical distance fallen through by the ball in the time of passage from the muzzle to the target, and the time in which it falls through this distance is given by the formula
t = √2sg
in which t represents the time, s the vertical space fallen through, and g the force of gravity. The distance to the target divided by this time gives the initial velocity approximately. Practically, this method is only applicable to large breech-loading cannon, which have neither windage nor vibration in the barrel to affect the angle of departure of the projectile. Smooth-bores or muzzle-loading rifles are subject to the first cause of error; the first-named guns in a great degree, and small-arms to vibrations not yet fully investigated, which cause a sensible difference between the axis of the piece as pointed and the line of fire. The causes that affect initial velocity are the weight of the charge, the size and position of the vent, the windage, the length of the bore, the form of the chamber, the diameter and density of the projectile, the windage of the cartridge; the form, size, density, and dryness of the grains of powder; and the barometric, thermometric, and hygrometric states of the atmosphere. See [Velocity].
Injuries to Cannon. Brass cannon are little subject to external injury caused by service, except from the bending of the trunnions sometimes, after long service or heavy charges. Internal injuries are caused by the action of the elastic fluids developed in the combustion of the powder, or by the action of the shot in passing out of the bore. These effects generally increase with the caliber of the piece. The principal injury of the first kind is the cutting away of the metal of the upper surface of the bore over the seat of the shot. The injuries of the second kind are, the lodgment of the shot,—a compression of the metal on the lower side of the bore, at the seat of the shot, which is caused by the pressure of the gas in escaping over the top of the shot. There is a corresponding burr in front of the lodgment, and the motion therefore given to the shot causes it to strike alternately on the top and bottom of the bore, producing other enlargements, generally three in number, the first on the upper side a little in advance of the trunnions, the second on the lower side about the astragal, the third in the upper part of the muzzle. It is chiefly from this cause that brass guns become unserviceable. Scratches, caused by the fragments of a broken shot, or the roughness of an imperfect one. A piece is said to be [honeycombed] when the surface of the bore is full of small holes and cavities. This is due to the melting and volatilization of a portion of tin in the alloy, tin being much more fusible than copper. Iron cannon are subject to the above defects in a less degree than brass, except the corrosion of the metal, by which the vent is rendered unserviceable from enlargement. The one cause of injury to iron cannon is the rusting of the metal, producing a roughness and enlargement of the bore and an increase of any cavities or honeycombs which may exist in the metal.
Iron cannon, however, are subject to a peculiar erosion by the gases, which Prof. Horsford explains by supposing that under the enormous tension and heat the sulphur in the gases unites with the iron, producing a friable sulphide of iron, which is successively formed and swept off by the gases. Wrought-iron guns are peculiarly subject to this erosion, cast-iron and steel less so. The amount of erosion is dependent upon the velocity with which the gases pass over the surface of the bore. In rifled wrought-iron guns having windage this action is fully illustrated, and the gun is soon disabled. The strong preference in many countries for steel as a bore lining is thus explained. By the use of expanding projectiles this action is largely prevented, the sabot acting as a gas-check. This system of projectiles is rapidly gaining favor for this and other reasons.
Inkerman. A small Tartar village in the Crimea, situated near the eastern extremity of the harbor of Sebastopol. It was once a celebrated city, and has numerous caverns cut in the rock, supposed to be the work of the monks in the Middle Ages. Near this place, November 5, 1854, was fought a battle between the allied English and French forces on the one side, and the Russians on the other, the former amounting to 25,000 or 30,000, the latter about 60,000. The Russians began the attack at dawn of day upon the intrenched lines of the English; but after a fierce and sanguinary contest of many hours, inflicting great loss on both sides, the Russians were finally driven from the field.