Early_Chronometer_Balance_Wheels.png

Summary

Description

English: Drawings of temperature-compensated marine chronometer balance wheels. These were designed during the 1st half of the 19th century by British chronometer makers attempting to improve on the standard Earnshaw balance, and win prizes at the British Admiralty Chronometer Trials. These are all attempts at solving the 'middle temperature problem'. An Earnshaw balance, when adjusted to keep time at high and low temperatures, gains as much as 4 seconds/day at middle temperatures from nonlinearity. The one on the right actually uses a tube of mercury for compensation. From Glasgow, David (1885), Watch and Clock Making , Cassell Co., p.247-256

Alterations to image: Collected five separate drawings from the book into one image

Français : Chronomètres de marine à température compensée.

Date

1885

Source

Downloaded source images from David Glasgow (1885), Watch and Clock Making , Cassell & Co., New York , p.247-256 on Google Books.

Author

Original source images: David Glasgow
Composite image: Chetvorno

Permission
( Reusing this file )

Public Domain - author died more than 70 years ago.

This work is in the public domain in its country of origin and other countries and areas where the copyright term is the author's life plus 70 years or fewer .

You must also include a United States public domain tag to indicate why this work is in the public domain in the United States. Note that a few countries have copyright terms longer than 70 years: Mexico has 100 years, Jamaica has 95 years, Colombia has 80 years, and Guatemala and Samoa have 75 years. This image may not be in the public domain in these countries, which moreover do not implement the rule of the shorter term . Honduras has a general copyright term of 75 years, but it does implement the rule of the shorter term. Copyright may extend on works created by French who died for France in World War II ( more information ), Russians who served in the Eastern Front of World War II (known as the Great Patriotic War in Russia) and posthumously rehabilitated victims of Soviet repressions ( more information ).

This file has been identified as being free of known restrictions under copyright law, including all related and neighboring rights.

Licensing

This work is in the public domain in its country of origin and other countries and areas where the copyright term is the author's life plus 70 years or fewer .

You must also include a United States public domain tag to indicate why this work is in the public domain in the United States. Note that a few countries have copyright terms longer than 70 years: Mexico has 100 years, Jamaica has 95 years, Colombia has 80 years, and Guatemala and Samoa have 75 years. This image may not be in the public domain in these countries, which moreover do not implement the rule of the shorter term . Honduras has a general copyright term of 75 years, but it does implement the rule of the shorter term. Copyright may extend on works created by French who died for France in World War II ( more information ), Russians who served in the Eastern Front of World War II (known as the Great Patriotic War in Russia) and posthumously rehabilitated victims of Soviet repressions ( more information ).

This file has been identified as being free of known restrictions under copyright law, including all related and neighboring rights.

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1885