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435

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•lids" 61 * equal parts, the more the truer the work, and runfi'otjj ^ ai ts on the dotted arch-line figure; then draw a line^ ott C(l i-° w bieh > 3 the soffit stretched out; then draw a8tr et t i ltle f*'° m the centre, a, the parts of the arch-line,f 4, ri | °ut far enough to receive the parts taken from the*tr<, t , llle to the inside of the wall, and set them on the soffit,

4 Hed

out.

as 1, 2, 3, 4, 5, 6, 7, 8, and so on; which will“7?- ed " e the soffit.

'H^ 9ure —a is a circular soffit in a circular wall, which' J' 1 ®’ ? n ^ le j am bs, ant * square at top; which makes the

hfti|, s !j‘o' n g as well as flewing. Draw the flewing of thej n o they meet at o. The outside-arch is a semicircle,

*^\v j', de ' arc h a semi-ellipsis. On the transverse diameter0 18 plan of the wall, and the chord-line, e d, equal toik* 1 ' 11 ® 0n the inside 1 c ; then, on the chord-line, e d,file e sem icircle, whose diameter is equal to e d; then, on°Pei 1 ; n e chord-line, draw the lesser semicircle to the outsideVal f ’ then draw the ellipsis, e d, whose height is exactlyJ? fe ater° t * le ^ le ‘oht of the lesser semicircle ; then divide the^ttej ,. Seni 'circle into a number of equal parts, and draw* aes from these parts to the inside curve of the wall;*l>ei n rPv a rule from the point o, to where those lines meet^ th e e °f the wall, and d raw the black lines across the planjVe 8 Wall > w hich will give the width of the soffit at those*hen draw, with the centre o, the two arch-lines?.%. and on the arch 1 b, run the parts on the greatVs ail( l> from the centre, o, to these parts, draw the black^ th e Cr ° ss the soffit, stretched out, as 1, 3, 5, 7, 9 ; then taket he r ^ arts between the great semicircle and the ellipsis, and1 ) 1,2 „ 0n the lines drawn across the soffit, stretched out,V’ 1 4,5,6,7,8,9,10, and trace through these points,

* t) le give the inside of the soffit ; then take the width

n ' . ' on the soffit,

which is the width of

on those black lines, and set it,«<% ° Ut> wil1 S‘ ve the line g if,

I, J^iie p),

(. yitrg 4 '°. w ’ n S are taken from the British Palladio :(Via,. , >8 a circular flewing soffit, in a circular walllike ,i the

U.

flewing of the jambs, till they meet at e; thenSi‘eat rad ' us ’ e °> and d raw the arch-line bo ; then divide(jV int Q e ^ and lesser arch into the same number of parts, as|> ei r , ’ tliis will do for a straight wall: as this planJVf ar | a ^> take half the distance of the chord-line of thetfr ^ di ■ ' n l * ie com P asses > an( l strike the dotted arch,|j "°, lc *e into four parts ; then set them on the chord-linet>D 8tr et t» an( l draw lines from them to the arch-

k ("‘e ch C 0 Bed out parallel to e 1; then take dg, the distanceC | 0 n, 0t ,° rd 'li ne of the plan and the curve, and set it fromi!° td 'lin l * le hue ^ e > then set the distances, 2, 3, 4, of the

V M 'Htie , - ....

f t 1 On t | ( a nd curve-line, and set from the arch-line stretchedt| ( **1 6 tQ e P ar allel lines, 2, 3, 4 ; trace through those points^'Vadtl*’ and ^ ou l |ave half the edg® °f the soffit. To get

make a section of the arch, as on the right of- °- 1 : draw the perpendicular lines, 1 5, 1 5, the

■ v* 4 >

of . ...

ltd tn ° on the plan ; then take the distances o, 2, 3, 4,

1 t 0 2 * tde perpendicular line to the right, as markedtli t( l'li lle ’ 4, 5, at right angles, the distances from the

Vj**’ aa d ° t * le S reat al 'ch, 1 1, 2 2, 3 3, 4 4, trace through1%’ Proc^ 0 , 1 *' aVe 0ne s ‘ de l * ds sect l° n > f° r the smaller' ed as before, and on the other perpendicularflij^ tl le „ ) 'e distances, as figured, 5, 4, 3, 2, 0; from 0 to 1and W ' n ® *' ne l * le arc h> at the cr °wn ; take thats et it from n to k, on the soffit; also, to the>li e 8s in ^ ai hne on the side of the plan, m, n, set the com-®ereti' aild ^'ike out the side of the flew to n ; divideVaf Part s Ce °f t '*e line 0 1, from the section to n, into as^ c Ur , aS *be great arch ; then set off those parts withe > respectively, from 2, 3, 4, 6, on the soffit; then,

with the parts 1, 2, 3, 4, on the greater dotted arch, crossthem from k ; trace through them, and you have half thesoffit ; mark them to the other side, and the soffit iscomplete.

“ Figure 6 is a circular flewing and winding soffit, in astraight wall. Continue the flewing of the jambs till theymeet at a; then draw the arch-line, b c, and make the chordsequal to the circumference of the lesser arch, on which setthe parts it is divided into, 1, 2, 3, 4 ; divide the distance ofthe chord from the arch into five parts; draw aline from 3 to b,and mark where it cuts the perpendicular 4 at d; draw a line,from d to 1, parallel to the chord-line ; divide 1 2 into fourparts ; from two of them, draw a line parallel to Id; markwhere it cuts the perpendicular of 3, on the chord-line at c ;draw another parallel line from the third mark, and mark itscrossing the perpendicular of 2, on the chord-line at h; tracethrough the points b, d, e, h, 2, this gives one side of the soffit;then take the ordinates across the plan, 1 1, 2 2, 3 3, 4 4, andthe side of the flew a f and set them from 2, h, e, d, b ; thentake the parts 1, 2, 3, 4, of the greater arch, and set themfrom 1 to 2, 3, 4 ,f; trace through them, and get the other side;set off these ; measure to the other half, and complete thesoffit.”

Plate II. j Figure 1.—A soffit, from the Practical HouseCarpenter. No. 1, is the plan and section of the centre.No. 2, is the covering extended in piano. The author describesit thus : “ Figure b the plan of a circular wall, wherein acircular door, or window, is to be fixed ; to make a soffit tofit or stand on the plar, as Figure d ; draw the base-line ofthe arch, or soffit, to touch the bow of the wall ; divide thearch-line into twelve parts, and drop them down to the planacross it ; then stretch out the arch, as 1 to 12, and drawthe divisions at right angles from it; then take them fromthe base-line to the wall, as 1, 2, 3, 4, &c. and transfer themon the parts of the line stretched out, will give the edge ofthe soffit d.”

Figure 2 .—A cylindrical soffit, cutting obliquely througha straight wall, from the Practical House Carpenter. 'I'heauthor describes it thus : “ Figure e is a soffit in a straightwall on flewing jambs ; r the soffit stretched out; stretchout the arch, as o to 8, and draw lines from those divisionsparallel with the jambs ; then draw the lines from the divi-sions on each side of the plan ; the angle of meeting will givethe edge of the soffit.” This description is imperfect : forthe true method, see the article Envelope .

Figure 3.—A cylindrical soffit in a circular wall, fromPain’s Practical Builder. The author describes it thus :

“ Figure a is a circular wall, which has a door, or window,that stands flewing. Because the'jambs do not stand at rightangles with the diameter of the circle, find the curve-line ofthe soffit in this case ; draw the chord-line, or base-line,of the arch, o 9, at right angles with the jambs o, h, to touchthe arch of the wall at a, and divide the arch into equal parts,and drop them to the wall ; then take off the distances h, g,8, 9, 7,/, 6, e, &c., and put them on the arch stretched out,gives the edge of the soffit.” It is singular, that this methodshould be true, while the former, winch is more simple,is false.

Fiqure 4.—A cono-cuneoidal soffit in a circular wall.No. 1, is the plan and sections of the centre: No. 2, thesoffit stretched out.

Figure 5.—A conical soffit in a cylindric wall, where theaperture expands towards the concave surface of the wall.

Figure 6.—A conical soffit in a circular wall, where theaperture expands towards the convex surface ol the wall.

Figure 7.—A cono-cuneoidal soffit in a circular wall, wherethe aperture expands towards the convex surface of the wall.