The definitive online guide to Heuer chronographs and dashboard timepieces
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According to the book "Mastering Time", by Brunner and Sich, Heuer patented the "Semicrograph" in 1916, with the timer having a balance frequency of 180,000 vibrations per hour and a precision of 1/50 of a second. (The "Micrograph", by contrast, established the record for a mechanical watch of the period, with an accuracy of 1/100 of a second.) "Mastering Time" and catalogs of the period indicate that the split second version of the Semimicrograph was called the "Semicrosplit" or the "Split Semicrograph" (see pages 62 and 82 of Mastering Time, where these different names seem to be used to describe the same timer). The timer shown below is clearly marked "Semikrograph" on the dial and is almost identical to the "Semikrograph" shown on page 63 of "Mastering Time". It is puzzling that both these timers are marked "Semikrograph", but have the split second feature (which suggests that they should have "split" somewhere in their names). Signature features of this timer are the copper-colored pushers and inner bezel.
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