PERSPECTIVE. 
which cuts off all divisions upon the side LE, 
and then raise the perpendiculars. The ga- 
ble-end is found exactly in the same manner 
as has been described, only taking care to 
use the proper distance-point H. The man- 
ner ot finding the width of the chimney is d.f- 
ferent. Lay off ba for the height of the 
chimney above the top of the gable, and draw 
ac parallel to the horizontal line; then put ac 
equal to the actual thickness of' the chimney, 
and draw ad to the vanishing-point A; draw 
also cd to the distance-point 1, cutting off ad 
in d: then having drawn ef from the nearest 
corner of the chimney, which was found as in 
fig. 10, draw df to the vanishing-point B, 
cutting off ef f6r the exact perspective width. 
Fig. 16 represents the method of finding the 
perspective of a circle in oblique perspective. 
AB is the horizontal line, C the centre of the 
picture, and D, E, the distance-points. The 
process is exactly the same as that just de- 
scribed ; the several divisions of the reticulated 
square in fig. 13, being laid upon the ground- 
line FG, and from these, lines are drawn to 
the distance-points. The perspective of the 
square is then drawn with all the lines across 
it, and the curve traced through the different 
points. 
By drawing these examples frequently over, 
to a large scale, and reflecting upon them 
with attention, the studentwill become familiar 
with their use; and as they include the cases 
which most frequently occur, he will neces- 
sarily find great benefit from the knowledge 
of them. 
The practical part of perspective, is only 
the application of these rules to the actual- 
description of objects. But, as this part is 
purely mathematical, its assistance towards 
drawing is alone what can be performed by 
rule and compass, and can therefore strictly 
serve only for finding the images of points, of 
which they are composed ; and, as these are 
infinite, it is endless to find them all by the 
strict rules ; whence it becomes necessary 
after a sufficient number of them are found, 
to complete the image by the help of draw- 
ing, to the better effecting of which these 
points serve as a guide. Thus, when a cir- 
cle is to be described, the practical rules serve 
to find a sufficient number of points in the 
circumference ; which, being neatly joined by 
hand, will perfect the imaged so that, in strict- 
ness, nothing in this image is found by ma- 
thematical rules, save the few particular 
points; the rest owes its being to the hand of 
the drawer. 
Thus also, if any complicated figure is 
proposed, it may not be easy to apply the 
practical rules to the description of every 
minute part ; but by inclosing that figure in a 
regular one, properly subdivided and reduced 
into perspective, that will serve as a help, 
whereby a person skilled in drawing, may 
with ease describe the object proposed. Upon 
the whole, where the boundaries of the pro- 
posed objects consist of straight lines and plane 
surfaces, they may be described directly by 
the rules of perspective; but when they' are 
curvilinear, either in their sides or surfaces, 
■the practical rules can only serve for the de- 
scription of such right-lined cases as may con- 
veniently inclose the objects, and which will 
enable the designer to draw them within 
those known bounds with a sufficient degree 
.©» exactness. 
It is therefore in vain to seek, by the prac- 
tical rules of perspective, to describe all the 
little hollows and prominences of objects, the 
different light and shade of their parts, or their 
smaller windings and turnings; the infinite 
variety of the folds in drapery ; of the boughs 
and leaves of trees, or the features and iimbs 
of men and animals ; much less to give them 
that roundness and softness, that force and 
spirit, that easiness and freedom of posture, 
that expression and grace, which are requisite 
to a good picture. Perspective must content 
itself with its peculiar province of exhibiting 
a kind of rough draught to serve as a ground- 
work, and to ascertain the general proportions 
and places of the objects, according to their 
supposed situations ; leaving the rest to be 
finished, beautified, and ornamented, by a 
hand skilful in drawing. 
It is true, perspective is of most use where 
it is most wanted, and where a deviation from 
its rules would be the most observable ; as in 
describing all regular figures, pieces of archi- 
tecture, and other objec ts of that sort, where 
the particular tendency of the several lines is 
most remarkable ; the rule and compass in 
such cases being much more exact than any 
description made by hand: but still the figure', 
described by the perspective rules, will need 
many helps from drawing ; the capitals, and 
other ornaments of pillars, and their entabla- 
tures, the strength of light and shade, the 
apparent roundness and protuberance of the 
several parts, must owa their beauty and 
finishing to the designer’s hand ; but, with re- 
gard to such objects as have no constant and 
certain determinate shape or size, such as 
clouds, hills, trees, rivers, uneven grounds, 
and the like, there is a much larger latitude 
allowable, provided the general bulk, or usual 
natural shape of those objects, are in some 
measure observed, so as not to make them 
appear unnatural or monstrous. See Draw- 
ing. 
But, although the strict practical rules of 
perspective are in a great measure confined 
to the description of right-lined figures, yet 
the knowledge of the general laws of that 
science is of great and necessary use to inform 
the judgment, after what manner the images 
ot any proposed lines should run, which way 
they should tend, and where terminate ; and 
thereby enables it the better to determine 
what appearance any objects ought to put on, 
according to their different situations and 
distances; it accustoms the eye to judge with 
greater certainty of the relations between real 
objects and their perspective descriptions, and 
the hand to draw the same accordingly, and 
directs the judgment readily to discover any 
considerable error therein which might other- 
wise escape notice. Besides that, when the 
ground, or general plan, and the prin- 
cipal parts of a picture, are first laid down ac- 
cording to the rules, every thing else will 
more naturally fall in with them, and ever y 
remarkable deviation from the just rules will 
be the more readily perceived, and the easier 
avoided or rectified; so that although it may 
be infinitely tedious, or absolutely imprac- 
ticable, to describe every minute part of a 
picture by the strict mechanical rules, yet the 
employing them, where they can be the most 
commodiously used, will give the picture in 
general such a look, as will guide the artist in 
drawing the other parts without any obvious 
inconsistency. 
We shall, therefore, give such rules as are 
of most general use in the practice of per- 
spective. i. Let every line which in the 
object or geometrical figure is straight, per- 
pendicular or parallel to its base, be so also 
in its scenographic delineation. 2. Let the 
lines, which in the object return at right 
angles from the fore-right side, be drawn 
scenographically from the visual point. 3. Let 
all straight lines, which in the object return 
from the fore-right side, run in a scenographic 
figure into the horizontal line. 4. Let the 
object you intend to delineate, standing on 
your right hand, be placed also on the right 
hand ot the visual point; and that on the left 
hand, on the left hand of the same point; and 
that which is just before, in the inriidle of it. 
5. Let those lines which are (in the object) 
equidistant to the returning line, be drawn in 
the scenographic figure, from that point found 
in the horizon. 6. In setting off the altitude 
of columns, pedestals, and the like, measure 
the height from the base-line upward, in the 
front or lore-right side; and a visual ray down 
that point in the front shall limit the altitude 
of the column or pillar, all the way behind 
the tore-right side, or orthographic appear- 
ance, even to the visual point. This rule you 
must observe in all figures, as well where there 
is a front or fore-right side, as where there is 
none. 7. In delineating ovals, circles, arches, 
crosses, spirals, and cross arches, or any other 
figure in the roof of any room, first draw it 
ichnographicaily ; and so with perpendiculars 
from the most eminent points thereof, carry 
it up into the ceiling; from which several 
points carry on the figure. 8. The centre in 
any scenographic regular figure, is found by 
drawing cross lines from opposite angles : for 
the point where the diagonals cross, is the 
centre. 9. A ground-plane of squares is alike, 
both above and below the horizontal line ; 
only the more it is distant above or beneath 
the horizon, the squares will be so much the 
larger or wider. 10. In drawing a perspective 
figure, where many lines come together, you 
may, for the directing of your eye, draw the 
diagonals in red: the visual lines in black; 
the perpendiculars in green, or other different 
colour from that which you intend the figure 
shall be ot. 11. Having considered the height, 
distance, and position of the figure, and drawn 
it accordingly, "with side or angle against the 
base, raise perpendiculars from the several 
angles or designed points, from the figure to 
the base ; and transfer the length of each per- 
pendicular, from the place where it touches 
the base, to the base on the side opposite to 
the point of distance; so will the diametrals 
drawn to the perpendiculars in the base, by 
intersection with the diagonals, drawn to the 
several transferred distances, give the angles 
of the figures, and so lines drawn from point 
to point will circumscribe the scenographic 
liguie. 12. If in a landscape there are any 
standing waters, as rivers, ponds, and the like, 
place the horizontal line level with the farthest 
sight or appearance or' it. 13. If there are any 
houses, or the like, in the picture, consider 
their position, that you may find from what 
point in the horizontal lines to draw the front 
and sides thereof. 14. In describing things 
at a great distance, observe the proportion 
both in magnitude and distance, in draught, 
which appears from the object to the eye.’ 
15. In colouring and shadowing of every 
Jung, ) °u must Jo the same in your picture. 
