Part 51

=Hanger=, illus. 179

=Helical Wheel= desc. 199, illus. 207

=Hemisphere=, def. 45

=Heptagon=, def. 47

=Hexagon=, def. 47 To Construct a 95

=Hexagon-Head Bolt=, illus. 144

=Hexahedron=, def. 48

=Horizontal=, def. 45, 250

=Horizontal Line=, in Drawing, illus. 250 How to Draw 32 In Perspective 252

=Hypothesis=, def. 83

=Icosahedron=, def. 48

=India Ink=, desc. and illus. 131 Dish or Tile, illus. 131

=India Rubber Eraser=, illus. 132 Use of 240

=Ink=, Preparing, for Drawings, desc. 167 Test for Good, desc. 167

=Ink Eraser=, Steel, desc. and illus. 132

=Inking=, illus. 166, 169 Long Lines, illus. 170 Rules of Procedure 168 Short Work, illus. 169

“=Inking in=” Drawings, desc. 167 “Points,” etc. 239, 243 Patent Office Drawings 234

=Inscribe=, def. 45

=Instrumental=, def. 45

=Instruments= for Chalk-work, illus. 29

=Internal Gear=, desc. 201

=Internal-Gear Wheel=, illus. 207

=Introduction= 15

=Isosceles Triangle=, def. 50

=Lantern-Wheel=, desc. 201

=Lathe-Dog=, illus. 76

=Lemma=, def. 83

=Lettering=, Blow-Off Valve, illus. 175 Drawings, desc. 171