HISTORY OF BELL

The Bell can be defined as a hollow vessel usually of metal,but sometimes of horn,wood,glass, or clay,struck near the rim by an interior clapper or exterior hammer or mallet to produce a ringing sound.Bells may be categorized as idiophones,instruments sounding by the vibration of resonant solid material,and more broadly as precussion instruments.The shape of bells depends on cultural environment,intended use,and material construction.The walls vary from straight to convex,concave,hemispherical,barrel shaped (as in East Asia ), and tulip shaped with sound bow(the bulge near therim),as are all tower bells the West.In cross section they may be round,square,rectangular,elliptical,or many-sided.Chinese bells often lotus-shaped rims.

The strongest sound-producing vibration of bells occur near the rim,in contrast to hollow gongs,the vibrations of which are strongest in the centre.The acoustical structure of the bell sound is complex and has been completely understood only in mordern times.All bells contain an array of partials,or sound wave frequencies of various pitches,but the tone of a musical bell consists of both harmonious partials and higher inharmonious partials.

Bells are widely distributed geographically and usually posses a clearly defined cultural status.Legends surround them,and beliefs around concerning their special powers-to induce ram or to dissolve storm clouds;to thwart demons when worn as amulets or to invoke curses and lift spells.The Chinese rang bells to communicate directly with the spirits,and in Russian orthodoxy,bells directlyaddressed the deity-hence ,huge ones were cast by both peoples to lend greater authority.In both Buddhism and Christianity,bells are consecrated before being used liturgically,and in East Asia the fading tone of the bell is considered spirutually significant.In Roman Catholicism,bells have symbolized paradise and the voice of God.

Among the most basic and widespread uses of bell is signalling-marking significant points of rituals,calling to worship ,tolling the hours,announcing events,rejoicing,warning,and mourning.In Christian and Asiatic Buddhist monasteries,bells regulate daily routine,and medieval and Christian bells were named according to purpose :squilla for the refectory,nola for the coir,and so forth.

The ancient Chinese were the first to employ sequences of bells musically;such sequences are termed chimes,or pien chumg.In the West since the 9th century,small sets of bells in stationary suspension and generally tuned diatonically(to the seven-note scale)have been common.Sets of tuned bells numbering at least 23 termed carillons.Sets of handbells ranging up to five octaves have been popular in England and the U.S. since the 19th centuary as a group method for producing melodies and simple harmonics.In the main the liurgical and utilitarian functions of bells have greatly diminished,whereas their musical usage has increased.

In bell founding,molten metal(usually bronze) is poured into a mould of an inner core and outer mould or cope cotoured to a bell's profile.Most moulds are faced ewith loam,those for handbells with sand.The liquid metal ,heated to about 1,100 deg.centigrade enters a hole at the top while being tamped (driven by a series of low blows) down through another.Large bells require a week or two to cool.If a certain pitch is required ,small amounts of metal are ground from the bell's inner wall as it revolves.Bell metal or bronze is an alloy of copper and tin.Tin content may range from 13% in weight to25%,rarely more.Tin increasesbrittelness,and large bells contain less than small ones do.

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