0.5

1 cm

[ 6* ]

supposed 70 degrees). Through C, draw C G, pa-

rallel to the line above R, and of equal length to the dis-

tance C I ; perpendicular to C G, erect C S : through

S, draw A S B parallel to CG; this is the vanishing

line for the plane proposed, S its center, and S G equal

to its distance.

This object has faces in three various inclinations;

first, that lying on the ground, which accordingly va-

nishes in the vanishing points to the ground, as d f and

e k ; secondly, other faces perpendicular to the ground, as

e k Ig\ thirdly, an inclined face not parallel to either,as

df I g ; which is our immediate object. E D F is an ori-

ginal plan, whose lines being continued strike the ground

line in R, and &c. Rule R to L, being coincident with

the ground plane ; and Q_ and its parallel to H ; by

which we obtain d f for the reprefentation of D F : and

by the same means, we obtain e k, which now completes

the perspedtive plan of the object. From d draw d

B ; from f draw f B : erect on ea perpendicular,

which cuts d B in /: and from / rule I L, cutting_/B in

g ; which completes the figure.

M K Shews the side-elevation of this object.

No. II. Figure 1. Represents an inclined plane, one

side of which is parallel to the picture : eredt on the

center a perpendicular at pleasure ; and at H, form such

an angle as the plane to be treated is supposed to make ;

as at K. Rule a line in that direction from FI, till it

intersects the perpendicular from C, as at I : through I,

rule a line parallel to H L, as V I; which being the

vanishing line to the plane, governs its perspective. To

I (its center), rule D and E; to C, the center of that

part coincident with the ground, rule DC; on a

erect a line, which cuts DI in A; from A, a line parallel

\ ts

supposed 70 degrees). Through C, draw C G, pa-

rallel to the line above R, and of equal length to the dis-

tance C I ; perpendicular to C G, erect C S : through

S, draw A S B parallel to CG; this is the vanishing

line for the plane proposed, S its center, and S G equal

to its distance.

This object has faces in three various inclinations;

first, that lying on the ground, which accordingly va-

nishes in the vanishing points to the ground, as d f and

e k ; secondly, other faces perpendicular to the ground, as

e k Ig\ thirdly, an inclined face not parallel to either,as

df I g ; which is our immediate object. E D F is an ori-

ginal plan, whose lines being continued strike the ground

line in R, and &c. Rule R to L, being coincident with

the ground plane ; and Q_ and its parallel to H ; by

which we obtain d f for the reprefentation of D F : and

by the same means, we obtain e k, which now completes

the perspedtive plan of the object. From d draw d

B ; from f draw f B : erect on ea perpendicular,

which cuts d B in /: and from / rule I L, cutting_/B in

g ; which completes the figure.

M K Shews the side-elevation of this object.

No. II. Figure 1. Represents an inclined plane, one

side of which is parallel to the picture : eredt on the

center a perpendicular at pleasure ; and at H, form such

an angle as the plane to be treated is supposed to make ;

as at K. Rule a line in that direction from FI, till it

intersects the perpendicular from C, as at I : through I,

rule a line parallel to H L, as V I; which being the

vanishing line to the plane, governs its perspective. To

I (its center), rule D and E; to C, the center of that

part coincident with the ground, rule DC; on a

erect a line, which cuts DI in A; from A, a line parallel

\ ts