Even the untrained eye can discern the fakes' inferiority compared with watches built by British masters like Thomas Tompion, George Graham, and Thomas Mudge.
FORBES: Magazine Article
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By Tompion's death, in 1713, daily variation was less than a minute, and by the late 19th century, marine chronometers were accurate to fractions of a second per day.
FORBES: Magazine Article
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When Thomas Tompion began making watches around 1670, the best ones money could buy had only an hour hand--and a tendency to gain or lose some 10 minutes per day.