Part 56

=Screw-Thread=, U. S. Standard Gauge 280

=Scroll or Curve=, desc. 117 Universal Curve, illus. 134

=Secant of an Arc= 99

=Section=, def. 49 Drawing illus. 163, desc. 160

=Sectional=, def. 49

=Section-Liner=, illus. 116

=Section Lines= in Drawings 240

=Section-Lining=, Cast-iron, etc., illus. 182 Cog-Wheel, illus. 183

=Section-Lining Drawings= desc. 182, illus. 183 Wheel Hub, illus. 184

=Selecting Drawing Instruments= 103, 240

=Semi-Circle=, def. 43

=Sensitized Paper=, desc. 188

=Set-Square=, illus. 102, 114

=Shading Curves=, illus. 181

=Shading Drawings= 180

=Shadow=, def. 49

=Shadow Line=, def. 46

=Shadow Lines=, “Points” 241

=Sharpening Pencils= 57

=Shop Drawings=, Office Rules 192

=Sight=, Point of, in Perspective Drawing 252 Sense of 254

=Sight Lines= in Projection, illus. 157

=Sine= of an Arc 99

=Skew-Gearing=, desc. 203

=Sketch Books=, desc. 142 Office Practice 194

=Sketches=, details 142

=Sketch=, Free-hand, Advantage of 55

=Sketching= desc. 141, note 17 Points to be observed in 141-2