ined, 85

Drawing-board, 11

Drawing instruments, 9

Drawings, advantage of large, 29

Drop and draw, 150

Duplex escapement, 131, 155

E

Elasticity of spring, 133

Engaging friction, 81

English recoil anchor, 167

Entrance lip of cylinder escapement, 125

Escapement angles, measuring, 101

Escapement error, study of, 64

Escapement matching tool, 106

Escapement model, 40
Balance, 42
Balance staff, 44
Bridges, 41, 42
Escape wheel, 43
Extra balance cock, 45
"Frosting", 46
Hairspring, 42
Jewel for, 43
Lower plate, 41
Main plate, 41
Movement for, 41
Pallet staff, 42
Pillars, 43
Regulator, 46
Uses of, 44
Wood base for, 41

Escapements compared, 103

Escapement of Dutertre, 160

Escape-wheel action, 30

Escape-wheel, delineating an, 11

Escape-wheel teeth vs. cylinder, 169

Escape-wheel tooth in action, delineating an, 126

Exit pallet, 26

Experiments of Galileo, 158

Experiments with a chronometer, 142

Extent of angular impulse, 118

F

"Fall" defined, 106

Faults in the detent escapement, 132

Fixed rules, of little value to student, 137

Flexure of gold spring, 146

Foot, fitting up the, 151

Fork, testing the, 71

Fork action, 30
Theory of, 59

Fork and roller action, 54

Formulas for delineating cylinder escapement, 115

Frictions, 24

Frictional escapement, 131, 132

Frictional surfaces, 63

Fusee, 131

G

Gable escapement, 167

Gage, a new, 172

Graham anchor escapement, 155

Gold spring, 146

Guard point, 79
Material for, 79

Gummy secretion on impulse and discharging stones, 147

H

Heights in cylinders, how obtained, 171

Hole jewels, distance apart, 140

I

Imaginary faults in cylinders, 129

Impulse angle, 118

Impulse arc, extent of, 134

Impulse jewel set oblique, 147

Impulse planes, locating outer angle of, 39

Impulse roller, 136

Incline of teeth, 122

Inertia of balance, 133

Inventions of
Berthoud, 163
Bethune, 165
Clement, 166
Dr. Hook, 162
Harrison, 161
Hautefeuille, 161
Huygens, 158
Leroy, 163
Thiout, 165

J

Jewel pin, determining size, 58
Cementing in, 67
Settings, 66

Jewel-pin setters, 67

L

Lathe cement, 173
Removing, 1