is derived. It was made the capital of the Province of Lusitania, and later became the seat of the Visigothic archbishops. It remained an important town during the time of the Moorish domination until it was captured by Alfonso IX. in 1228. Its population in 1900 was 9124.
MER′IDEN. A city in New Haven County, Conn., 18 miles north-northeast of New Haven, and the same distance south-southwest of Hartford; on the New York, New Haven and Hartford, and the Meriden, Waterbury and Middletown Railroad, a branch of the former (Map: Connecticut, D 3). It is picturesquely situated, overlooked by the Hanging Hills on the northwest, and is drained by Harbor Brook. Meriden is one of the most prosperous industrial centres in New England. Among its manufactures are silver and plated ware, hardware, cutlery, steel pens, bronzes, brass castings, malleable iron, firearms, organs, self-playing attachments for pianos and organs, glassware, cut glass, curtain fixtures, gas and kerosene fixtures, screws, vises, and machinery. The city has the Connecticut School for Boys (Reform), Meriden Hospital, Curtis Home for Orphan Children and Aged Women, and the handsome Curtis Memorial Library. Hubbard Park is a beautiful natural reservation of 900 acres, within the limits of which are the Hanging Hills, the highest point rising 1000 feet above sea level. Another attraction is Lake Merimere.
The government, under a charter of 1897, is vested in a mayor, elected every two years; a bicameral council; and administrative officials, appointed or elected as follows: by the mayor—boards of apportionment and taxation, public works, and police, fire, and park commissioners; by the council—tax-collector, plumbing inspector, fire marshal, boiler inspector, health officer, and board of compensation; by the people—clerk, treasurer, auditor, and sheriffs. The city owns and operates its water works. Population, in 1890, 21,652; in 1900, 24,296. From 1725 until incorporated in 1806 as a town under its present name (probably from Meriden, Eng.), Meriden was a parish of Wallingford. In 1867 it was chartered as a city. Consult Perkins, Historical Sketches of Meriden (West Meriden, 1849).
MERID′IAN (Lat meridianus, relating to midday, from meridies, for *medidies, midday, from medius, middle + dies, day). Any great circle of a sphere passing through its poles. A terrestrial meridian is the intersection of the earth's surface made by a plane passing through the poles. A celestial meridian is a great circle of the celestial sphere passing through the celestial poles. The prime meridian is the one from which longitude is measured. The magnetic meridian at any point is the horizontal direction at the point of a freely suspended compass needle undisturbed by influences other than the earth's magnetic force. To distinguish the terrestrial or geographical meridian from the magnetic, the former is called the true meridian, as its direction is that of true north or south. It is evident from the explanation given that the so-called magnetic meridian is not a great circle of the earth, but merely a direction at a particular point. The line joining the points of equal variation are not therefore coincident with the magnetic meridian; they are called isogonic lines, and, owing to the non-uniform character of the earth's magnetic force, these lines are very irregular curves. See Meridian Circle; Meridian Measurement.
MERIDIAN. A city and the county-seat of Lauderdale County, Miss., 87 miles east of Jackson; on the Queen and Crescent Route and the Southern Railway (Map: Mississippi, H 6). It is the seat of the East Mississippi Female College (Methodist Episcopal), opened in 1869, and of the Meridian Academy (Methodist Episcopal South), and Lincoln School (Congregational), the last two for colored students. The city has an extensive trade, due to its position in a cotton-growing region, and is the most important manufacturing centre in the State. Its industries, represented by railroad machine shops, cotton mills, cottonseed oil mills, lumber mills, etc., had, by the census of 1900, a production valued at nearly $3,000,000. Meridian was an important Confederate railway centre during the Civil War, and in February, 1864, General Sherman was sent against it. Arriving on the 14th, he remained unmolested until the 20th, completely destroying the railroads in the vicinity and demolishing the large store-houses and many private residences. Population, in 1890, 10,024; in 1900, 14,050.
MERIDIAN CIRCLE. An instrument used for determining the meridian altitude or zenith distance of a star. It consists of an astronomical telescope firmly fixed to a graduated circle, which moves about a horizontal axis, resting on a pair of very solid supports. In the common focus of the eye-piece and object-glass of the telescope is a system of fixed cross-wires (spider lines are generally used for the purpose), one being horizontal, and five or more vertical, with equal spaces between. An imaginary line passing through the optical centre of the object-glass and the intersection of the horizontal and middle vertical wires is called the line of colliniation of the telescope, and, when the instrument is in perfect adjustment, this line moves in the plane of the meridian. Besides the above-mentioned fixed wires there is a movable one, called a micrometer wire, which is moved by means of a screw, remaining always parallel to the fixed horizontal wire. If the instrument is in perfect adjustment, and if the image of a star, while passing across the middle vertical wire in the field of view, is at the same time bisected by the fixed horizontal wire, the star is at that moment in the line of collimation of the telescope. It is therefore at that moment in the meridian, and its meridian zenith distance is the angle through which the circle would have been turned from the position it had when the line of collimation of the telescope pointed to the zenith. There is a fixed pointer, for the purpose of approximately reading the instrument. If the instrument was adjusted so that the pointer was opposite the zero point of the circle, when the line of collimation of the telescope pointed to the zenith, the arc measured on the circle between these two positions of the instrument is the meridian zenith distance of the star.
Great nicety is required in reading the instrument; i.e. in determining exactly the arc through which the circle has moved in bringing the telescope from the vertical to any other position. The rim is usually graduated at intervals of five minutes; and the eye could determine only the division nearest to the fixed index. But by means of a reading microscope or micrometer (q.v.),
