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.

PREFACE

The aim of this treatise is to make a clear presentation of the
theory of projection, to show the application of this theory as a
medium of expression, and by the discussion and proof of a great
variety of problems to enable the student to make a ready and
intelligent use of this medium in the representation of all forms
of magnitudes.
As by far the greater part of practical drafting is done from
the standpoint of the third quadrant, there seems to be no good
reason why the principles of descriptive geometry, which are so
directly and extensively applied in practice, should not also be
presented from the standpoint of the same quadrant.
Therefore, while the student is called upon to work freely in
all the four quadrants, the subject-matter is presented primarily
from the third quadrant.
In the establishment of principles great effort is made to be
explicit; but in the application of these principles, for which
purpose a great many unsolved problems are assigned, the student
is left largely to his own resources.
As the principles of projection are fundamental in all branches
of drafting, it follows that no attempt at extensive application of
these principles in such subjects as machine drawing, gearing,
architectural drawing, etc., should be made until the principles
themselves have been thoroughly established. For this reason
the attention of this work is largely confined to theoretical considerations, although a number of simple practical applications such
as the student can safely and intelligently make are introduced.
iii