Page:Cyclopaedia, Chambers - Volume 2.djvu/685

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the apparent Altitudes, as in the preceding Articles. If now their upper Lines be connected by curve Lines, as in the Bafe, a, b, d, f, c, h, e, c, the Stenography of the Cir- cle will be compleat.

'Tis evident that thofe Lines are to be omitted, both in the Plan and in the Elevation, which are not expofed to the Eye ; though they are not to be disregarded, from the Beginning, as being neceflary for the finding of other Lines. E. gr t In the Scemgraphy of the Cube, viewed Angle wife, the Lines b d and d c, (Fig. 2.) in the Bafe, and the d h in the Elevation, are hid from the Eye, and are therefore omitted in the Defcription. But fince the Point h is not to be found unlels the Point d be had in the Ichwgraphy ; nor the Lines g h and d e be drawn without the Height d h; the Appearance of the Point d is as necefTary to be determined in the Operation, as the Height hd.

right Lines P V and O V. 5. Then, from n, j, I, trf raile Perpendiculars, the Middle ones whereof are cm by the right Line O V in o, and the Extremes, by the right Line V P in p. Thus will the Door be delineated, with its Pofts. If the Door were to have been exhibited in the Wall EF GH, the Method were nearly the fame. For, i°. Upon the Terreltrial Line, fet off the Diftance of the Door from the Angle, and thence alio the Breadth of the Door R T. 2. From R and T, draw right Lines to the Principal Point V, to have the Breadth r t in the perfpeftive Plan. 3 °. -.From r and t, raife indefinite Perpendiculars to F H. 4. From A to O, let off the true Height A O. Laftly, From O, to the principal Point V, draw the right Line O V, inter feeling E F in Z, and make r r and t t equal to T Z. Thus is the Door r r, 1 1 3 drawn, and the Potts are eafily added, as before.

To exhibit the Scenooraphy of a ^Pyramid, Jland- To exhibit the ing on its Safe.

ScENOGRAPHY of WIDOWS in

a Wall.

Suppofe, e, gr. it were required to delineate a Qua- drangular Pyramid, viewed by an Angle : i°. Since the Bale of fuch Pyramid is a Square feen by an Angle, draw iuch a Square. a. To find the Vertex of the Pyramid, i. e. a Perpendicular let fall from the Vertex to the Bafe, draw Diagonals mutually interfering each other in e {Fig. 5.) 3°- ^n an y P°J nt » as H, of the Terreftrial Line D E, raife the Altitude of the Pyramid HI; and drawing the right Lines H V, and I V to each Point of the Horizon- tal Line H R ; produce the Diagonal a b, till it meet the Line V H in h. Laftly, From h draw h i parallel to H I, This being railed on the Point e, will give the Ver- tex of the Pyramid c d; confequently, the Lines d k,

k a, and k b, will be determined at the fame Time.

After the like Manner is the Stenography of a Cone de- lineated.

To exhibit the S c e. n o g a a p it y of a Trun- cated ^Pyramid.

Suppofe the Truncated, Pyramid Quadrangular; i°, then, If from the feveral Angles of the upper Bale be conceived Perpendiculars let fall to the lower Bale, we .mall have a Pentagon, with another inferibed therein, whole Sides are parallel to thofe of the former. This coincides with a Pentagon, furnilfied with a Rim or Breadth, ££?c, and may therefore be delineated in the fame manner.—- 2. Railing the Altitude of the Truncated Pyramid (IH, Fig. 6.) deter- mine the Scenographic Altitudes, to be railed in the Points a b, c, d. If now the Points f, g, h, i, k, be connected by right Lines, and the Lines, 1 k, f m, g n, h 0, be

drawn, the Scemgraphy will be compleat. By drawing

two concentric Circles in a Geometrical Plan, and doing every Thing elle, as in this Problem, the Scenography ot a Truncated Pyramid will be drawn.

To exhibit the Scenography of Walls, Columns, ckc.

or to raife them on the ^Pavement.

lo. Suppofe a Pavement A F H I (Fig. 7.) repre- f en ted in a Plan, together with the Bales of the Co- lumns, fi?c, if there be any. 2 . Upon the Terreflrial Line fet off the Thicknefs of the Wall B A and 1, 3. 3 . Upon A and B, as alfo upon 3 and 1, raile Perpendi- culars A D and B C T as alfo 3, 6, and 1, 7. 4 . Connect the Points D and 6 with the Principal Point V, by the right Lines D V and 6 V. j°. Upon I and H raife Perpendiculars H G and E F. Thus will all the Walls be delineated. Now to raife the Pillars, gefc, there needs nothing but, from their feveral Bales (whether Square, or Circular) projected on the Peifpeftive Plan, to raife indefinite Perpendiculars; and on the Fundamen- tal Line, where interfered by the Radius Fa palling through the Bafe, raife the true Altitude A D: for D V, being drawn as before, the Sce?iographical Altitudes will be determined.

To exhibit the Scenography of a 1)cot in R

Building.

Suppofe a Door required to be delineated in a Wall DE FA (Fig.7.) i°. Upon the Fundamental Line fet off its Diftance A N from the Angle A, together with the Breadths of the Pofts N I and L M, and the Breadth of the Gate itfelf L I. 2. To the Point of Diftance K, from the leveral Points N, I, L, M, draw right Lines K N, K I, K L, KM, which will determine the Breadth of the Door 1 i, and the Breadths of the Tofts c n and m 1. 3 . From A to O, fet off the Height of the Gate A O, and from A to P, the Height of the Pofts A P, 4. Joya O and P with the Principal Point,, by the

When you .know how to repreTent Doors, you'll find no Difficulty in adding Windows ; all that is here further required, being to fet off the Height of the Window from the Bottom of the Ground. The Whole Opera- tion is as follows. i Q. From 1 to 2, let of the Thick- nefs of the Wall at the Window ; from 3 to 4, its Di- ftance from the Angle 3 ; and from 4 to 5 its Breadth. 2°. From 4 and 5, to the Point of Diftance L, draw the right Lines E 5 and L 4, which will give the Per- spective Breadth 10, 9 of the Window. 3 . From iq and 9 raife Lines perpendicular to the Pavement; i. e. draw the parallel Lines 6, 3. 4°. t From 3 to n fet oft" the Diftance of the Window from the Pavement 3, n; and, from 11 to 12, its Height m, 12. Laftly, From 11 and 12, to rhe principal Point V, draw Lines Vij and V 12; which interfering the Perpendiculars 10, 13, and 9, 14, in 13 and 14, as alio in 15 and 16, wilt exhibit the Appearance of the Window.

From thele Examples, which are all no more than Applications of the firft grand general Rule, it will be ealily perceived what Method to take to delineate any other Thing, and at any Height from the Pavement.

A Mechanical Method of exhibiting the Scenography of any Objeil ; See under the Article Designing.

SCENOPEGlA, a Feaft among the Jews', more ufii- ally called, The Feafi of Tabernacles, inftituted after the People of Ifrael were in Poffcffion of the Land of Canaan* in Memory of their having dwelt under Tents in the Wilderneis. 'Twas held for 8 Days fucceflivcly, com- mencing on the Fifteenth of September. The laft Day was much the moft lolemn, both on Account of the Con- flux of Perlbns, and of the extraordinary Tokens they gave of their Joy. 'Tis of this Eighth Day, St. Johtt muft be underftood to fpeak, when he tells us, our Savi- our was at the Feaft of Tabernacles, on the laft and great Day. Wheri the Holy Scripture fays abfolutely, tloe Feafl, 'tis to be ufually underftood of the Sccmpegia. The Word is Greek, form'd of okwyi Scene, Tabernacle, Tent ; and wryvvyu Figo, I fix.

SCEPTER, a Royal Staff, or Battoon, born, ; on So- lemn Occasions, by Kings, as a Badge of their Command and Authority. See Regalia. The Scepter is an En- fign of Royalty of greater Antiquity than the Crown. The Greek Tragic, and other Poets, put Scepters in the Hands of the moft ancient Kings they ever introduce. Jtiflin ob&wts, That the Scepter, in its Original, was a Ha(ia or Spear: He adds, That in the moft remote An- tiquity, Men adored the jjaftce, or Scepters, as immortal Gods; and, that it was upon this Account, that even, in his Time, they ftill furnifhed the Gods with Scep- ters. "Neptune's Scepter is his Trident, See Trident. Tarquin, the Elder, was the firft who aflumed the Scepter among the Romans. Le Gendre tells up, That in the firft Race of the French Kings, the Scepter was a Golden Rod, almoft always of the fame Heighth with the King who bore it, and crooked at one End like a Crosier. Fre- quently, inftead of a Scepter, they are feen on Medals with a Palm in their Hand. Nicod derives the 'word from the Greek aaojVW, which he fays, originally "g nl " fied a Javelin, which the antient Kings ufually bore as a Badge of their Authority, in regard that Inftrument was in very great Veneration among the Heathens. B ur » "in Effect, etw'&T&v does not properly fignify a Javelin, but as a Staff, to reft upon, from axxm\a, Innitor^ l}& a -

Scepter, Sceptrum^ in Anatomy, one of the Six new Couftellations of the Southern Hemifphere, cenfiftmg °* 1 7 Stars; one of the 4th Magnitude, g of the 5 th, and as manv of the £th.

SCEPTICISM, the Doctrine and Opinions of the Scepticks; called alfo Tyrrhonifm, from the Name of i ts Author. Sec Pyrrhonism.. The Ancient Scepticifmf™'

lifted