Page:Cyclopaedia, Chambers - Volume 2.djvu/329

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call the Chain, as it holds 'em together ; that the Group befuftain'd by fomething loofe and diftincf from it; and by the fame join'd and continued to the other Groups : And that the Lights and Shadows be fo difpofed, as that we may at once fee the Effefls of all the Parts of the Compofition. See Group.

2. To the JBions, wherein forced Attitudes are to be avoided ; and fimple Nature fhewn in her moft advanta- geous Poftures. In weak and lean Figures, the Nudities not to be /hewn ; but occafions of covering 'em fought. In all human Figures, fpecial Care to be taken, the Head be well placed between the Shoulders ; the Trunk on the Haunches, and the whole on the Feet. See Atti- tude.

5. To the Drsfery ; which is to be adjufled fo, as it may appear real Garments, and not Stuffs loofely thrown on. The Folds to be fo difpofed, as to leave the great parts wherein the Nudity may appear, free ; ranging the little Folds about the Joints, and avoiding 'em on the Re- lievo of the Members. And, laftly, to difpofe the Dra- peries, by railing the Stuff, and letting it fall lightly, that the Air fuftaining the Folds, may let 'em fall foft. See Drapery. ■ ,

Laftly, in the Contraft, are to be confider d the Actions, which vary infinitely : The Afpefls, which, in Affions of the fame kind, may, by their difference, make a Contraft : The Situation, according as they meet above or under the Sight, far or near. And, laftly, the Cuftom; which ex- tends, indeed, to ail parts of Painting, but is particularly to be regarded in the Ordonnance ; to be managed difcretely, however, and ftiffnefs and formality avoided. See Con- trast.

Oreonnance, in Architecture, is nearly the fame as in Painting ; viz. the Difpofition of the Parts of a Building, both with' regard to the whole, and to one another. See Building.

Vttruvms defines OrdonmtiK to be that which regulates the Size of all the Farts of a Building with refpeft to their Ufe.

This Definition is cenfur'd byM.Terrault, who takes the Ordonnance to confift in the Divifion of the Plan or Spot of Ground whereon the Building is to be rais'd ; i. e. in the apportioning or laying it out, agreeable with the intended Dimcnfions of the whole Fabric ; which Mr. Evelyn ex- preffes in fewer Words by the determining of the Meafures of what is affign'd to compofe thefeveral Apartments.

On this Foundation, Ordonnance is the judicious Contri- vance of the Plan or Model ; as when the Court, Hall, Lodgings, i£c. are neither too large nor too little .- But the Court, 11.gr. affords convenient Light to the Apartments about it, and is large enough for ufual Accefs. The Hall of fit Capacity to receive Company ; the Bed-Chambers accordingly, £?""• When thefe Divifions are either too great or toofmall with refpecl to the Place, as a large Court to a little Houfe, or a little Chamber in a magnificent Palace ; the f.ult is in the Ordonnance.

This the Antients call'd Taxis; and diftinguifhed it from Dialhejis, Difpofition; which is, where all the Parts and Members ofaBuilding are affign'd their juft Place andSitua- tion with regard to their Quality, Office, Rank, &c. without any regard to the Dimenfions or Quantity : As, that the Vettible or Porch precede the Hall, the Hall the Parlor, that the Withdrawing Room, ilc. The Bed-Chambers, •aoain, to the Sun-rifing ; Libraries, Galleries of Paintings, and Cabinets of Curiolities, \$c. to the North. ORE, fee Oar. -

ORGAL, the Lees of Wine dried, and ufeci by Dyers to prepare the Cloth for more readily taking their feveral Colours. See Dying, Colour, Tartar, igc.

ORGAN, in Mufic, the largcft and moft harmonious of all Wind-Inftruments. See Music.

The Invention of the Organ is very antient, tho' it is agreed it was very little ufed till the VMth Century. It feems to have been borrow'd from the Greeh. Vitruviits defctibes one in his tenth Book. The Emperor Julian has an Epigram in its praife. St. Jerom mentions one with twelve Pair of Bellows, which might be heard a thoufand Paces or a Mile ; and another at Jerufalem, which might be heard to the Mount of Olives. The Structure of the modern Organ may be conceiv'd as follows.

The Organ is a Buffet containing feveral Rows of Pipes. The Size of the Organ is ufually exprefs'd by the length of its largeftPipe : Thus we fay an Organ of 52 Feet, of it. Feet, of 8 Feet, and of 2 Feet. Church Organs confift of two Parts, viz. the main Body of the Organ, call'd the Erect Organ ; and the Fojitive, or little Organ, which is a fmall Buffet ufually placed before the great Organ.

The Organ has at leaft one Ser of Keys, when it has only one Body ; and two or three, when it has a Pofitive. The large Organs have four, fometimes five Sets. Befides, the Pedals or largeft P'pes havetheir Key, the Stops orTouches whereof are play'd by the Feet. The Keys of an Organ

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are ufually divided into four Ocfaves ; viz* the fecond Sub-Oftave, firft Sub-Oc~tave, middle Oftave, and firft Oclave. Each Oclave is divided into twelve Stops or Frets j whereof thefeven black mark the natural Sounds, and the five white the artificial Sounds ; i. e. the Flats and Sharps. So that the Keys ufually contain 48 Stops, or Touches. Some Organifts add to this Number one or more Stops in the third Sub-Octave, as well as in the fecond. Note, in Harpfichords and Spinets, the natural Stops or Keys are ufually mark'd white, the artificial ones black. The Pedals have about two or three Octaves at the pleafure of the Organift : So that the number of Stops is undeter- minate.

Each Key or Stop prefs'd down, opens a Valve or Plug, which correfponds, lengthwife, to as many Holes as there are Rows of Pipes on the Sound-Board. The Holes of each Row are open'd and iliut by a Regifter or Ruler pierced with 48 Holes. By drawing the Regifter, the Holes of one Row are open'd, becaufe the Holes of rhe Regifter correfpond to thofe of the Sound-board. So that by opening a Valve, the Wind brought into the Sound- board by a large Pair of Bellows, finds a PafTage into the Pipe which correfponds to the open Hole. of the Sound- board. Butby pufhing the Regifter, the 48 Holes of the Regifter, not anfwering to any of thofe of the Sound- Board, that Row of Pipes anfwering to the pufii'd Regiiler are /hut. Whence it follows, that by drawing feveral Re- gi iters, feveral Rows of Pipes are open'd 5 and the fame thing happens, if the fame Regifter correfpond to feveral Rows. Hence the Rows of Pipes become either Simple or Compound 5 Simple, when only one Row anfwers to one Regiiler j Compound, where feveral. The Orga- nifts fay, a Row is Compound^ when feveral Pipes play upon preffingone Stop.

ThcPipes of the Organ are of two kinds ; the one with Mouth$, like our Flutes 5 the other with Reeds. The firft call'd Pipes of ~Mt>.tation y confift,

1. Of a Foot A A B B, (Tab. Music, Fig. 1.) which is a hollow Cone, and which receives the Wind that is to found the Pipe. 2. To this Foot is faften'd the Body of the Pipe B B D D. Between the Foot and the Body of the Pipe is a Diaphragm, or Partition E E F, which has a little, long, narrow Aperture to let out the Wind. Over this Aperture is the Mouth B B C C 5 whofe upper Lip CC being level, cuts the Wind as it comes out at the Aperture.

The Pipes are of Pewter, Lead mix'd with a twelfth Part of Tin; and of Wood. Thofe of Tin are always open at their Extremities j their Diameter is very fmall their Sound very clear and fhrill. Thofe of Lead mix'd', are larger j the ftiorteft open, the longeit are quite ftop'd ; the mean ones partly ftop'd, and having beiides a little Ear on each fide the Mouth, to be drawn clofer, or fet further afunder, in order to raife or lower the Sound. The wooden Pipes are made fquare, and their Extremity ftop'd with a Valve or Tampion of Leather. The Sound of the wooden and leaden Pipes is very foft ; the large ones ftop'd, are ufually of Wood j the fmall ones of Lead. The longeft Pipes give the greateft Sound 5 and the fhorteft the moft acute : Their Lengths and Widths are made in the reciprocal Ratio's of their Sounds 5 and the Divifions regu- lated by their Rule, which they call Diapafan. But the Pipes that are /hut only have the Length of thofe that are open, and which yield the fame Sound. Ufually, the longeft Pipe is r 6 Feet 5 tho' in extraordinary Organs 'tis 32. The pedal Tubes are always open, tho' made of Wood and of Lead.

A Reed-Fife confifts of a Foot A A B B, (Tab. Music, Fig. 2.) which carries the Wind into the Shalot, or Reed CD, which is a hollow Demi-cylinder, fitted at its Extremity D, into a kind of Mould I I, by a wooden Tampion F G. The Shalot is cover'd with a Plate of Copper E E F F, fitted at its Extremity F F into the Mould by the fame wooden Tampion : Irs other Extre- mity EE isat liberty 5 fo that the Air entring the Shalot, makes it tremble or fhake againft the Reed ; and the longer that part of the Tongue which is ar liberty FL, is made, the deeper is the Sound. The Mould I [, which ferves to fix the Shalot or Reed, the Tongue, Tampion* &c. ferves alfo to flop the Foot of the Pipe, and to oblige the Wind to go out wholly at the Reed. Laftly, in the Mould is folder M the part HHK K, call'd the Tube, whofe inward opening is a continuation of that of the Reed. The Form of this Tube is different in the different Ranks of Pipes.

The degree of Acutenefsand Gravity in the Sound of a Reed-Pipe, depends on the Length of the Tongue, and that of the Pipe C K, taken from the Extremity C of the Shalot, to the Extremity K of the Tube.

The Quality of the Sound depends on the Width of the Reed, the Tongue, and the Tube ; as alfo on the Thick- nefs of the Tongue, the Figure of the Tube, and the Quantity of Wind.

To