no A R C H I T 
into any number of equal parts, draw ordinates to the plan 
B, as a, b. From the raking-line e, d, draw the corre- 
fponding ordinates at right angles with it; and by the 
compafies transfer the feveral ordinates from 3 to G, as 
a, b, to c, d, and 1, 2, 3, 4, relpeftively : then, by drawing 
a curve line through thele points, G will become an ac¬ 
curate mould for the upper fide of the hand-rail. 
But, as the twifl of the hand-rail requires a greater fub- 
fiance of wood than the ftraight part, this may eafily be 
determined thus: Draw the fquare of the hand-rail on the 
pitch-board, as a in fig. 7; and parallel lines from the op- 
poftte angles will fliew the thicknefs required, as at 1, 2. 
Agreeably to this, /, m, n, in jig. 8, fliew the manner of 
glueing the rail with the additional thicknefs of wood be¬ 
fore defcribed. It is made of fo many pieces, and varied 
in glueing, to aflift in more eafily forming the twill. The 
belt method, in faft, is to glue thefe in the ftraight way ot 
the grain, by which, if the wood be properly matched, 
the whole will appear one folid piece. To reduce thefe 
pieces properly, and to produce in the whole twift an 
agreeable turn, it will be requilite to have a falling mould, 
that when each part of the twift is fo fquared, as in every 
part to anfwer to a perpendicular line over its plan when 
placed in its due pofition, it may be applied to the outfide 
of the rail round the twift. In Jig. 5, therefore, confider 
D the pitch-board and OP the level of the fcroll at 3, 4. 
Take the ftretph of a line fuppofed to be girted from 1 to 
3, jig. 3, which transfer to OP at D. Divide each fide of 
the angle formed by the raking and level line into any 
number of equal parts, as 1, 2, 3, each way, and the points 
produced by the interfeftions of the lines drawn from each 
divifion, will form a curve, perfectly eafy and fufliciently 
accurate for the pttrpofe. 
If a fcroll is required to take its fpring from any part of 
the fecond ftep, then draw the pitch-board as at Jig. 6, and 
proceed in every particular as before. Fig. 9, is a plan of 
a hand-rail, including five fteps. M is the quarter-plan, 
and D is the pitch of five fteps; and R the face-mould 
for the hand-rail if it be cut out of the folid; if other- 
wile, thin veneers are glued round a cylinder made for the 
purpofe, and on which mull be marked each ftep and rifer 
as (hewn at A, that the thin flips at b for the hand-rail, and 
t hole at a for theftringing-board, may be correClly laid down. 
To illuftrate this fubjedt as much as poffible by engra¬ 
vings, we have given plans of eight different kinds of 
Staircafes: /rg. 10, is a geometrical fquare; n, is the el¬ 
liptical form; 12, is a trapezia; 13, a parallelogram ; 14, 
the triangular ; 15, the circular; 16, the odtangular; and 
17, the femicircular form ; all of which are now occafion- 
ally executed in London, upon geometrical principles, with 
fuch magnificence and grandeur, as both excite ouradmira- 
tion, and juIlly difplay the improved ftate of fcience in that 
great metropolis. 
From this variety of plans for ftaircafes, it will be eafy 
to feledt fuch as might be adapted to almoft every fpecies 
of building, from the princely palace to the rural cot¬ 
tage. But before any kind of ftaircafe is eredled, it is ne¬ 
ceflary that the following general rules fhould be well con- 
lidered. Firft, the height of the floor to which we are 
to af'cend. Secondly, the rife, and number of fteps that 
are neceflary for the height. Thirdly, to divide the num¬ 
ber of fteps by fuch haff-fpaces (or breathing-places) as 
are neceflary for repofing on the way. Fourthly, that the 
ipace above the head, commonly called head-way, be fpa- 
cious. And, laftly, that the breadth of the afcent be pro¬ 
portionable to the whole building, and fufficient for the 
purpofe intended ; fo as to avoid encounters by perfons af- 
cending and defcending at the fame time. The light to a 
ftaircafe fhould always be liberal, to avoid flips, falls, &c. 
and which may proceed from the fides, from a cupola, or 
fky-light at the top, as the fituation will beft admit. 
And, before this kind of work is begun, it is beft to make 
a plan, and to lay out the whole in ledgement, as follows : 
Let t, q, 9, 11, at Jig. 18, of the fame Plate, be the gi¬ 
ven plan; make ds equal to the breadth of th« afcent, 
E C T U R E. 
which may be made from three feet and a half to ten feet. 
Draw db, b a, and am, parallel to the outlines of the plan. 
Divide db, ba, and am, each into fuch a number of fteps, 
whole feveral heights are equal to the whole height to be 
afeended ; within the parallelogram a bmd, draw the thick¬ 
nefs of the hand-rail. Add into one fum the heights of 
the feveral fteps, between b and d, and at that diftance 
draw qr, parallel to os; draw the'hypothenufal line rs, 
and continue out the plan of each ftep to meet the line rs 
at s ; fet up the height of the firft ftep, and draw it paral¬ 
lel to os, until it meet the bafe-line of the fecond ftep ; 
then fet lip the height of the fecond ftep, and draw it pa¬ 
rallel to os-, proceed in like manner to fet up the heights 
of all the remaining fteps unto r: make op equal to 0 q, 
and draw 2 p parallel to to ; at the point 2, begin to let up 
the fteps unto the point j, and draw v s parallel to to: 
make t w equal to tv, and draw w 8 parallel to 1 9; at g 
begin to let the fteps as aforefaid unto i, then will it be 
equal to the height of the ftory, and the feveral figures 
oq rs, opisvt, twgiqy, will be the fides of the ftaircafe 
laid out in ledgement, as required. The plan, fig. 19, is 
in like manner reprefented above, which may be con fide r- 
ed as its ledtion, wherein Im is the height to be afeended; 
g h the firft flight, ho the half-fpace ; h i the fecond flight, 
in the half-fpace ; ik the laft flight, whofe landing, as the 
workmen term it, is Ik. 
The next thing to be confidered is the manner of placing 
the newels to (fairs and half-fpaces. In fig. 20, the half- 
fpaces are made fquare to the angles of the newels, which 
caufes the hand-rail of the firft flight to drop the height of 
two fteps below the rail of the fecond flight. In fig. 21, 
the ftait s are fet to the middle of the newel, which caufes 
its rail to drop two fteps; and in fig. 22, they are placed 
to the outfide of the newel, and drop but one ftep. Thus 
variations may be made, to fuit a variety of cafes, as the 
architect, under different circumftances, judges necelfary. 
Of LINES for DESCRIBING SOFFITS and NICHES. 
Soffits denote any timber-ceilings formed of crofs-beams 
of flying cornices, whether plain or enriched ; or the un¬ 
der fide of a corona, arch, or architrave ; or the covering 
of any furface whatever with wood, fpread out on a plane. 
To dej'cribea Soffit in aJlraight Wall,fiuing equally allround y 
with a circular Head .—Let the fides of the plan A be con¬ 
tinued, as in the annexed Plate, at fig. 1, that is <2 c and 
bd to meet ate; then about the centre c, and from the 
points a and c, deferibe the foffit C, and ftretch the femi- 
circle B along the outfide of the foffit C, and it will be 
completed.— Dcmonjlration. Conceive the femicircle B to 
be turned at right angles to the plan A, then every point 
in the circumference of the femicircle B will be at an 
equal diftance from the point e; but the foffit C is defcri¬ 
bed with the fame radius, therefore the edge of the foffit 
C, that is, the arch-line af, will exadlly coincide with the 
arch of the femicircle B, which was required to be proved. 
To deferibe a Soffit in a circular Wall, fining equally all 
round, with a circular Head, as in fig. 2, of the annexed 
Plate.—The (fretch-out of this foffit is managed in the 
fame manner as the foregoing; and, for the other parts, 
proceed as follows: Draw the ordinates of the femicircle 
B, as fliewn in the figure; continue them to fi the centre 
of the flue, and at the points a b c de, where they interfect 
the plan, draw the parallel lines ae, bf, eg, &c. and from 
the points efg/i, circle lines to abed, round the centre f, 
which will give the half of one edge of the foffit, the 
other half being pricked from it; the reverfe edge i<g to 
be found in the fame manner. Obferve that this cannot 
be pricked from the plan, as the others are, becaufe the 
lines round the flue are not level with the plan, but will 
be longer than thofe on the plan.— Dcmonjlration. It is ea¬ 
fy to conceive, from the firft example, that if the femi¬ 
circle B is turned up, and the foffit at C bent round it, the 
points 1234, at C, will coincide with the equal divifions 
in the femicircle B, and the points abed, at C, will fall 
perpendicularly over the points abcd i in the plan A ; for 
