occupy four degrees.

MAKE A LARGE ESCAPEMENT MODEL.

Reason would suggest the idea of having the theoretical keep pace and
touch with the practical. It has been a grave fault with many writers on
horological matters that they did not make and measure the abstractions
which they delineated on paper. We do not mean by this to endorse the
cavil we so often hear--"Oh, that is all right in theory, but it will
not work in practice." If theory is right, practice must conform to it.
The trouble with many theories is, they do not contain all the elements
or factors of the problem.

[Illustration: Fig. 94]

Near the beginning of this treatise we advised our readers to make a
large model, and described in detail the complete parts for such a
model. What we propose now is to make adjustable the pallets and fork to
such a model, in order that we can set them both right and wrong, and
thus practically demonstrate a perfect action and also the various
faults to which the lever escapement is subject. The pallet arms are
shaped as shown at _A_, Fig. 94. The pallets _B B'_ can be made of steel
or stone, and for all practical purposes those made of steel answer
quite as well, and have the advantage of being cheaper. A plate of sheet
brass should be obtained, shaped as shown at _C_, Fig. 95. This plate is
of thin brass, about No. 18, and on it are outlined the pallet arms
shown at Fig. 94.

[Illustration: Fig. 95]

[Illustration: Fig. 96]

[Illustration: Fig. 97]

[Illustration: Fig. 98]

To make the pallets adjustable, they are set in thick disks of sheet
brass, as shown at _D_, Figs. 95, 96 and 97. At the center of the plate
_C_ is placed a brass disk _E_, Fig. 98, which serves to support the
lever shown at Fig. 99. This disk _E_ is permanently attached to the
plate _C_. The lever shown at Fig. 99 is attached to the disk _E_ by two
screws, which pass through the holes _h h_. If we now place the brass
pieces _D D'_ on the plate _C_ in such a way that the pallets set in
them correspond exactly to the pallets as outlined on the plate _C_, we
will find the action of the pallets to be precisely the same as if the
pallet arms _A A'_, Fig. 94, were employed.

[Illustration: Fig. 99]

To enable us to practically experiment with and to fully demonstrate all
the problems of lock, draw, drop, etc., we make quite a large hole in
_C_ where the screws _b_ come. To explain, if the screws _b b_ were
tapped directly into _C_, as they ar