34

The shapes of the lining pen points 35

Oil stoning pen points 36

Preparing the circle pen for use 38

The shape for circle pen points 38

Shaping circle pens for very small circles 39

A form of pen point recently introduced; forming the pen point 39

The method of oil-stoning circle pen points 40

The needle point and pen point 42

How to use the circle pen 43

German instrument to avoid slipping of a needle point 44

How to use the lining pen 45

Applying the ink to the bow-pen 46

Using a straight line or lining pen with a T square 47

CHAPTER III.

LINES AND CURVES.

Explanation of simple geometrical terms; radius; explanation of
conventional dotted lines 48

A line at a right angle to another; a point; parallel lines 49

A line produced; a line bisected; a line bounding a circle; an arc of a
circle; segments of a circle; the chord of an arc; a quadrant of a
circle 50

A sector of a circle; a line tangent to a circle; a semicircle; centre of
a circle; axis of a cylinder; to draw a circle that shall pass through
three given points 51

To find the centre from which an arc of a circle has been struck; the
degrees of a circle 52

The protractor 53

To find the angle of one line to another 54

To find the angles of three lines one to the other 55

Acute angles and obtuse angles 57

Triangles; right angle triangle; obtuse angle triangle; equilateral
triangle; isosceles triangle 58

Scalene triangle; a quadrangle; quadrilateral or tetragon 59

Rhomboid; trapezoid; trapezium 60

The construction of polygons