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A Complete and Practical Guide for Watchmakers in Adjusting Watches and
Chronometers for Isochronism, Position, Heat and Cold.

BY CHARLES EDGAR FRITTS (EXCELSIOR),

Author of "Practical Hints on Watch Repairing," "Practical Treatise on
Balance Spring," "Electricity and Magnetism for Watchmakers," etc., etc.

This well-known work is now recognized as the standard authority on the
adjustments and kindred subjects, both here and in England. It contains
an exhaustive consideration of the various theories proposed, the
mechanical principles on which the adjustments are based, and the
different methods followed in actual practice, giving all that is
publicly known in the trade, with a large amount of entirely new
practical matter not to be found elsewhere, obtained from the best
manufacturers and workmen, as well as from the author's own studies and
experiences.

Sent postpaid to any part of the world on receipt of $2.50 (10s. 5d.)

THE KEYSTONE (SOLE AGENT),
19TH AND BROWN STREETS, PHILADELPHIA, U.S.A.

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THE ART OF ENGRAVING

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A Complete Treatise on the Engraver's Art, with Special Reference to
Letter and Monogram Engraving. Specially Compiled as a Standard
Text-Book for Students and a Reliable Reference Book for Engravers.

This work is the only thoroughly reliable and exhaustive treatise
published on this important subject. It is an ideal text-book, beginning
with the rudiments and leading the student step by step to a complete
and practical mastery of the art. Back of the authorship is a long
experience as a successful engraver, also a successful career as an
instructor in engraving. These qualifications ensure accuracy and
reliability of matter, and such a course of instruction as is best for
the learner and qualified engraver.

The most notable feature of the new treatise is the instructive
character of the illustrations. There are over 200 original
illustrations by the author. A very complete index facilitates reference
to any required topic.

Bound in Silk Cloth--208 Pages and 216 Illustrations.

Sent postpaid to any part of the world on receipt of price, $1.50 (6s.
3d.)

PUBLISHED BY THE KEYSTONE,
THE ORGAN OF THE JEWELRY AND OPTICAL TRADES,
19TH & BROWN STS., PHILADELPHIA, U.S.A.

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THE KEYSTONE PORTFOLIO OF MONOGRAMS

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