Project Gutenberg's An Analysis of the Lever Escapement, by H. R. Playtner

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Title: An Analysis of the Lever Escapement

Author: H. R. Playtner

Release Date: June 30, 2007 [EBook #21978]

Language: English

Character set encoding: ASCII

*** START OF THIS PROJECT GUTENBERG EBOOK AN ANALYSIS OF THE LEVER ***

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[Illustration: THOMAS MUDGE

_The first Horologist who successfully applied the Detached Lever
Escapement to Watches._

_Born 1715--Died 1794._]

AN ANALYSIS

OF THE

LEVER ESCAPEMENT

BY H. R. PLAYTNER.

A LECTURE DELIVERED BEFORE THE CANADIAN WATCHMAKERS' AND RETAIL
JEWELERS' ASSOCIATION.

ILLUSTRATED.

CHICAGO:

HAZLITT & WALKER, PUBLISHERS.

1910.

PREFACE.

Before entering upon our subject proper, we think it advisable to
explain a few points, simple though they are, which might cause
confusion to some readers. Our experience has shown us that as soon as
we use the words "millimeter" and "degree," perplexity is the result.
"What is a millimeter?" is propounded to us very often in the course of
a year; nearly every new acquaintance is interested in having the metric
system of measurement, together with the fine gauges used, explained to
him.

The metric system of measurement originated at the time of the French
Revolution, in the latter part of the 18th century; its divisions are
decimal, just the same as the system of currency we use in this country.

A meter is the ten millionth part of an arc of the meridian of Paris,
drawn from the equator to the north pole; as compared with the English
inch there are 39+3708/10000 inches in a meter, and there are
25.4 millimeters in an inch.

The meter is sub-divided into decimeters, centimeters and millimeters;
1,000 millimeters equal one meter; the millimeter is again divided into
10ths and the 10ths into 100ths of a millimeter, which could be
continued indefinitely. The 1/100 millimeter is equal to the 1/2540 of
an inch. These are measurements with which the watchmaker is concerned.
1/100 millimeter, written .01 mm., is the side