PERSPECTIVE. 
diminution of the trapezia in proportion to 
distance. 
Fig. 2, shews the angle formed by two 
ranges of buildings, each of which has a dif- 
ferent vanishing point. N O is the perpen- 
dicular edge of the angle ; N Q O, and 
N P O, shew the two faces, each of which 
is intersected by streets of various breadths. 
In both instances the spectator’s eye is 
supposed to be situated near two-thirds up 
the two buildings ; that is to say, about X 
on one face, and about W on the other. 
This produces a mixed effect, seldom to be 
found in reality ; though in some cases, 
where streets lying on a declivity, and 
joining others with less deviation from the 
level, this will be produced. The mode of 
proving the due direction of lines in per- 
spective, such as X Q, and W P, which ap- 
pear like the bands or fillets that separate 
the different stories of an edifice, is very 
simple ; namely, all horizontal lines in 
buildings that decline from the plane of a 
picture, and tend towards some vanishing 
point, will, when above the spectator’s eye, 
appear to descend towards that point, as 
from N to Q i but when below the specta- 
tor’s eye, they will appear to rise as O Q. 
The triangle O Q N being more acute will 
give a more direct view of the houses, and 
appear to recede less from the eye than 
N P Q, which is more obtuse, and makes 
every liouse appear narrower. 
Fig. 3, shews the front of a house, 
I H F G, which, when thrown into perspec- 
tive by the vanishing point, Q, being made 
high, and several rays proceeding from 
opqrst to k being carried too high, give 
an o«tr^ appearance to the front as shewn 
by the outlines I F L M, in which it will be 
seen that a rude and unpleasant dispropor- 
tion is given in every part. Nor is this even 
the manner in which the house would ap- 
pear when seen from above, or below it ; 
on the principle of a bird’s eye view. The 
places of the several doors and windows 
being ascertained, the several lines, opqrst, 
intersect the ground-line F M in those parts 
which correspond witli the places of the 
doors ; whose heights are ascertained or de- 
termined by the line S Q, equal at S F to 
their height in the original front IHFG. 
The windows being over the doors, must 
be under the same perpendiculars in both 
cases ; their depth is determined by taking 
the measurements on the line I S, and 
drawing rays to the point Q. This figure 
is given chiefly with the intention of shewing 
the immense disproportions which are gene- 
rated by a false placing of the point to 
which the rays proceed ; and which point is 
always formed to advantage rather below 
than above the centre of a picture. When 
the horizon is too much raised, numberless 
distortions take place. 
Fig. 4, gives the ground plan of a gallery, 
R S V T, which is to be shewn in perspec- 
tive with its several standards, and the pitch 
of the awning on the ground lines V X and 
WX. Here II <j> becomes the horizontal 
line, on which X is the vanishing point, and 
<1> the point to which the luys R 4 >, 9 •!>, J 0 ij>, 
and W <]> being drawn, cut V X in the places 
marked 4, 3, 2, 1, respectively', and give 
the situations of the standards for the right 
side. The places for those on the left side 
are found by drawing the lines 5,4; 6, 3 ; 
7,2; 8, 1 ; all parallel to W V. In this in- 
stance all the intervals, R, 9 ; 9, 10 ; 10, W ; 
and W,V ; being equal, the proximate supe- 
rior ray will always give that parallel: thus 
the ray of R (ji cuts X W exactly at the 
point 6, which gives the line 6, 3, parallel 
to 7, 2 ; and so of all in succession. The 
lines Y Z and W V are parallel ; they deter- 
mine the height of the front standards, and 
by means of the lines Y X and Z X cut the 
other standards at their proper heights. 
Their ilescent towards X shew them to be 
above the line rr o, which is level with the 
spectator’s eye. The summits of the 
couples are ascertained by the line A X. 
They will all have their centres over the 
centres of the lines 5, 4; 6, 3; 7, 2; and 
8, 1 ; ascertained by drawing a line from B 
to X. 
F’ig. 5, exhibits the wall of a monastery, 
supported in some parts by reinforcements, 
or pillars, between which the wall is less 
substantial. The measurement of the pil- 
lars and of the inteiwals is given on the base- 
line A B, while G F shews the horizon and 
line of sight. The l ays from a, c, e, and g, 
shew the places where the several divisions 
take place on the ground-line A E, and 
shew the projections of b, d,f, h. The up- 
per line is also determined by C D, and the 
crosses in like manner are made to diminish 
towards the vanishing point F. The small 
mark at A in the middle of the wall’s thick- 
ness, as shewn by the shaded part, gives 
rule for each projection of the several pil- 
lars, as shewn by the shaded parts : their 
summits and bases will, however, have their 
fronts, t. e. the parts parallel with C A, ter- 
minated by horizontal lines parallel with 
A B. We must once more impress, that 
all fronting horizontals in nature must be 
