[Illustration: Fig. 10]
From the point _e_, which represents the center of the pallet staff, we
draw through _b_ the line _e f_. At one degree below _e f_ we draw the
line _e g_, and seven and one-half degrees below the line _e g_ we draw
the line _e h_. For delineating the lines _e g_, etc., correctly, we
employ a degree-arc; that is, on the large drawing we are making we
first draw the line _e b f_, Fig. 10, and then, with our dividers set at
five inches, sweep the short arc _i_, and on this lay off first one
degree from the intersection of _f e_ with the arc _i_, and through this
point draw the line _e g_.
From the intersection of the line _f e_ with the arc _i_ we lay off
eight and one-half degrees, and through this point draw the line _e h_.
Bear in mind that we are drawing the pallet at _B_ to represent one with
eight and one-half degrees fork-and-pallet action, and with equidistant
lockings. If we reason on the matter under consideration, we will see
the tooth _A_ and the pallet _B_, against which it acts, part or
separate when the tooth arrives at the point _c_; that is, after the
escape wheel has moved through ten and one-half degrees of angular
motion, the tooth drops from the impulse face of the pallet and falls
through one and one-half degrees of arc, when the tooth _A''_, Fig.
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