Part 223

JEE POTR, Ind. a statement and decree.

JEHAUNDER, Ind. a term used in India, signifying the possessor of the world.

JEHAUN GEER, Ind. a term used in India, signifying the conqueror of the world.

JEHAUN SHAH, Ind. king of the world.

JEHOULDAR, Ind. Treasurer.

JELOUDAR, Ind. belonging to the train or equipage.

JEMADE, Ind. the Indian word for month.

JEMIDAR or JEMMADAR, Ind. means a captain or chief of a company; it is the title of a black officer who has the same rank as a white lieutenant in the E. India company’s service. The author of the history of the Carnatic calls Jemidars or Jemmadars, captains either of horse or foot.

JENIZER-EFFENDI, an appointment among the Turks, which in some degree resembles that of provost-marshal in European armies. The only functions which this officer is permitted to exercise are those of judge to the company. He sits on particular days for the purpose of hearing the complaints of the soldiers, and of settling their differences. If a case of peculiar difficulty should occur, he reports the same to the Aga, whose opinion and determination are final.

JERSEY, an island on the coast of Normandy in France, which has belonged to the English ever since the Norman conquest. Although this island, as well as that of Guernsey, is still governed by the ancient Norman laws, it is nevertheless subject to the British mutiny act in many particulars.

JERUMONA, Ind. Mulct, fine, or penalty.

JETH, Ind. the name of a month which in some degree coincides with our month of May.

JET, Fr. a term signifying the motion of any body that is urged forward by main force; it likewise means the space which is gone over by any propelled body.

JET des bombes, Fr. This word has been adopted instead of Tir, which formerly expressed the course that a shell took when it was thrown out of a mortar by the power of gunpowder.

We sometimes use the words flight and range, to express the same action and progress.

The jet or flight of a bomb usually forms a curved line; but many engineers assert, that when the mortar is placed horizontally, it describes the three movements that are made by a cannon ball, viz. The violent or strait forward one, the mixed or curved, and the natural one, which is perpendicular.

It is particularly incumbent upon the officers who superintend the mortar duty, to ascertain, by a correct observation of the eye, the exact distance to which he means to throw the bomb. With this view he must give as many degrees of elevation as may be found necessary by the judgment he has formed.

In order to obtain some degree of certainty he first throws a bomb, by way of experiment, and he increases or diminishes his degrees of elevation according to the distance it runs, and from the spot on which it falls.

These are the only rules which are generally followed by those officers who have the direction of mortars. However, according to St. Remi the French bombardiers frequently make use of tables in order to calculate precisely the different lines of extent according to the different elevations of the mortar, particularly with respect to the degrees of the square rule from 1 to 45·

Although this method has been sanctioned by various and innumerable experiments, it has nevertheless been exposed to some censure. Mr. Blondel has written a treatise on the subject. This engineer asserts, that he has discovered a way of firing true, which exceeds all former inventions.

We are of opinion, that the best method must be that which is founded upon practical and daily experience. Those men who are in the continual habit of exercising in mortar duty, and who can form just calculations, especially with regard to the quality and quantity of gunpowder, will always be esteemed in preference to the most profound theorists.

According to the experiments which have been made by bombardiers with respect to the flight of bombs, a mortar is said to propel or urge forward in proportion to the quantity and quality of the gunpowder, by which it is charged.

A mortar, for instance, which has twelve inches calibre, and which is loaded with two pounds of mealed gunpowder gives a difference in its flight of 48 feet from one degree to another; and 2160 feet in its greatest extent under the elevation of 45 degrees.

The same mortar gives a difference, from one degree to another, of 60 feet, provided there be two pounds and a half of the same powder in its chamber, and it gives 2700 feet, for its greatest flight.

It finally gives 72 feet difference from one degree to another, if the charge consists of three pounds of mealed gunpowder, and the elevation be taken at 45 degrees, which in the opinion of bombardiers, is the greatest flight, taking a range of 3240 feet.

Among the French bombardiers there are tables put out according to this calculation, which may be found in Blondel or St. Remi. These tables are adapted to mortars of 12 inches calibre, which weight we have taken for example.

JET, among the French is likewise applied to the range taken by a fusee, as jet de la fusee, the flight of a fusee.

In cannon founderies it is further used to express the different pipes or hollows which are made of clay or wax, in order to convey the liquid metals into their moulds. In this sense it means cast, so that jet may be properly called a vent or aperture which is made at the extreme end of the mould and through which the metal is poured.