0.5

1 cm

[ 64 ]

No. III. Is a representation os a bureau, with the

£ap open , which is much the same as the trap door.

No. 4, Plate VII: e is its hinge,/its edge, a b c the cir-

cle it forms in opening, O O on the line OX, two points

which assist to draw the circle by ; X the diltance os

that circle : A is one side of the bureau perpendicular to

the picture, and B the ground line.

PLATE X.

No. I. Figure r, Represents a prism (one of whose

sides is perpendicular to the ground) retting on an in-

clined plane: This figure is an advance on No. 2,

Plate VIII. C is the center of H L, the horizontal line’;

Z is the original plane, and Y the prism handing on it.

Draw through C, a line perpendicular to it, as V C O:

place the prism V at the point of distance H, and rule

lines equal to the angles it makes, to O and to V ;

through these points, O and V, draw lines parallel to

H L, which thus become vanishing lines to its upper

and under saces. The surfaces of Z and of Y being

parallel, have the same vanishing point (O). The plane

B, Figure i, follows exadtly No. 2, Plate VIII. take g h

for the seat of A on B ; from V draw V g, V b, beyond

g and h ; and by the diagonal N g prolonged beyond

gy cutting V h in b, we obtain one termination of this

face, which is completed by ruling a b parallel to g b.

now rule for the other face a O, b O, which, cut by the

diagonal b K, will give c d for the termination of the

other face ; or, it may be found, by erecting a perperv

dicular from g to c, and drawing c d. ef on the ground

line mark the width of A.

In Figure 2, the plane A is construdted in a similar

manner with B in Figure i. eg vanishes in V; and/de-

notes

No. III. Is a representation os a bureau, with the

£ap open , which is much the same as the trap door.

No. 4, Plate VII: e is its hinge,/its edge, a b c the cir-

cle it forms in opening, O O on the line OX, two points

which assist to draw the circle by ; X the diltance os

that circle : A is one side of the bureau perpendicular to

the picture, and B the ground line.

PLATE X.

No. I. Figure r, Represents a prism (one of whose

sides is perpendicular to the ground) retting on an in-

clined plane: This figure is an advance on No. 2,

Plate VIII. C is the center of H L, the horizontal line’;

Z is the original plane, and Y the prism handing on it.

Draw through C, a line perpendicular to it, as V C O:

place the prism V at the point of distance H, and rule

lines equal to the angles it makes, to O and to V ;

through these points, O and V, draw lines parallel to

H L, which thus become vanishing lines to its upper

and under saces. The surfaces of Z and of Y being

parallel, have the same vanishing point (O). The plane

B, Figure i, follows exadtly No. 2, Plate VIII. take g h

for the seat of A on B ; from V draw V g, V b, beyond

g and h ; and by the diagonal N g prolonged beyond

gy cutting V h in b, we obtain one termination of this

face, which is completed by ruling a b parallel to g b.

now rule for the other face a O, b O, which, cut by the

diagonal b K, will give c d for the termination of the

other face ; or, it may be found, by erecting a perperv

dicular from g to c, and drawing c d. ef on the ground

line mark the width of A.

In Figure 2, the plane A is construdted in a similar

manner with B in Figure i. eg vanishes in V; and/de-

notes