ith soap and water and the shellac dissolved
away with alcohol. The final polish is obtained on the zinc lap with
Vienna lime and alcohol. Where lathe cement is used for securing the
regulator to the plate _A_, the alcohol used with the Vienna lime
dissolves the cement and smears the steel. Diamantine and oil are the
best materials for polishing when the regulator bar is cemented to the
plate _A_.

KNOWLEDGE THAT IS MOST ESSENTIAL.

_The knowledge most important for a practical working watchmaker to
possess is how to get the watches he has to repair in a shape to give
satisfaction to his customers._ No one will dispute the truth of the
above italicised statement. It is only when we seek to have limits set,
and define what such knowledge should consist of, that disagreement
occurs.

One workman who has read Grossmann or Saunier, or both, would insist on
all watches being made to a certain standard, and, according to their
ideas, all such lever watches as we are now dealing with should have
club-tooth escapements with equidistant lockings, ten degrees lever and
pallet action, with one and one-half degrees lock and one and one-half
degrees drop. Another workman would insist on circular pallets, his
judgment being based chiefly on what he had read as stated by some
author. Now the facts of the situation are that lever escapements vary
as made by different manufacturers, one concern using circular pallets
and another using pallets with equidistant lockings.

WHAT A WORKMAN SHOULD KNOW TO REPAIR A WATCH.

One escapement maker will divide the impulse equally between the tooth
and pallet; another will give an excess to the tooth. Now while these
matters demand our attention in the highest degree in a theoretical
sense, still, for such "know hows" as count in a workshop, they are of
but trivial importance in practice.

We propose to deal in detail with the theoretical consideration of
"thick" and "thin" pallets, and dwell exhaustively on circular pallets
and those with equidistant locking faces; but before we do so we wish to
impress on our readers the importance of being able to free themselves
of the idea that all lever escapements should conform to the rigid rules
of any dictum.

EDUCATE THE EYE TO JUDGE OF ANGULAR AS WELL AS LINEAR EXTENT.

For illustration: It would be easy to design a lever escapement that
would have locking faces which were based on the idea of employing
neither system, but a compromise betw