volume is the result. We present
it to the trade and students of horology happy in the knowledge that its
contents have already received their approval. An interesting addition
to the book is the illustrated story of the escapements, from the first
crude conceptions to their present perfection.

CONTENTS

CHAPTER I.

THE DETACHED LEVER ESCAPEMENT 9

CHAPTER II.

THE CYLINDER ESCAPEMENT 111

CHAPTER III.

THE CHRONOMETER ESCAPEMENT 131

CHAPTER IV.

HISTORY OF ESCAPEMENTS 153

CHAPTER V.

PUTTING IN A NEW CYLINDER 169

INDEX 177

WATCH AND CLOCK ESCAPEMENTS

CHAPTER I.

THE DETACHED LEVER ESCAPEMENT.

In this treatise we do not propose to go into the history of this
escapement and give a long dissertation on its origin and evolution, but
shall confine ourselves strictly to the designing and construction as
employed in our best watches. By designing, we mean giving full
instructions for drawing an escapement of this kind to the best
proportions. The workman will need but few drawing instruments, and a
drawing-board about 15" by 18" will be quite large enough. The necessary
drawing-instruments are a T-square with 15" blade; a scale of inches
divided into decimal parts; two pairs dividers with pen and pencil
points--one pair of these dividers to be 5" and the other 6"; one ruling
pen. Other instruments can be added as the workman finds he needs them.
Those enumerated above, however, will be all that are absolutely
necessary.

[Illustration: Fig. 1]

We shall, in addition, need an arc of degrees, which we can best make
for ourselves. To construct one, we procure a piece of No. 24 brass,
about 51/2" long by 11/4" wide. We show such a piece of brass at _A_,
Fig. 1. On this piece of brass we sweep two arcs with a pair of dividers
set at precisely 5", as shown (reduced) at _a a_ and _b b_. On these
arcs we set off the space held in our dividers--that is 5"--as shown at
the short radial lines at each end of the two arcs. Now it is a
well-known fact that the space embraced by our dividers contains exactly
sixty degrees of the arcs _a a_ and _b b_, or one-sixth of the entire
circle; consequently, we divide the arcs _a a_ and _b b_ into sixty
equal parts, to represent degrees, and at one end of these arcs we
halve five spaces so we can get at half degrees.

[Illustration: Fig. 2]