Elements of descriptive geometry, with applications to isometric projection and othe forms of one-plane projection; a text-book for colleges and ingineering schools by O. E. Randall.

14

DESCRIPTIVE GEOMETRY

below H. The horizontal projection m,-n, is parallel to M-N, and
makes the same angle with G-L that lM-N makes with V. That
portion of the horizontal projection included between m, and n, is
equal to the distance between M and N.
In the same figure O-P represents a straight line in the third
quadrant, parallel to Vbut oblique to H. The horizontal projection
o,-p, is parallel to G-L and at the same distance back of G-L
that O-P is back of V. The vertical projection o'-p' is parallel

FIG. 11 FIG. 12

FIG. 13

FIG. 14

to O-P and makes the same angle with G-L that O-P makes with
H. That portion of the vertical projection included between o' and
p is equal to the distance between O and P.
Fig. 12 shows how the projections of Fig. 11 will appear after
H and V take their position of coincidence.
In Fig. 13, Ml-N represents a straight line in the second quadrant and oblique to both H and V.