t pencil lines only may be
shown, and as the pencilling progresses to the right-hand, the
development may progress so that at the other or left-hand end, the
finished inked in and shaded thread may be shown, and between these two
ends will be found a part showing each stage of development of the
thread, all the lines being numbered in the order in which they were
marked. This prevents a confusion of lines, and makes it more easy to
follow or to copy the drawing.

It is the numerous inquiries from working machinists for a book of this
kind that have led the author to its production, which he hopes and
believes will meet the want thus indicated, giving to the learner a
sufficiently practical knowledge of mechanical drawing to enable him to
proceed further by copying such drawings as he may be able to obtain, or
by the aid of some of the more expensive and elaborate books already
published on the subject.

He believes that in learning mechanical drawing without the aid of an
instructor the chief difficulty is overcome when the learner has become
sufficiently familiar with the instruments to be enabled to use them
without hesitation or difficulty, and it is to attain this end that the
chapter on plotting mechanical motions and the succeeding examples have
been introduced; these forming studies that are easily followed by the
beginner; while sufficiently interesting to afford to the student
pleasure as well as profit.

NEW YORK, _February, 1883_.

CONTENTS.

CHAPTER I.

THE DRAWING BOARD.

The T square 18

The triangles 19

Curves 21

Selecting and testing drawing instruments 22

Lead pencils 23

Mixing India ink 25

The drawing paper 26

Tracing paper 29

The ink 30

Testing and selecting India ink 30

Draftsmen's measuring rules 33

CHAPTER II.

THE PREPARATION AND USE OF THE INSTRUMENTS.

Preparing the lining pen for use