Pocket watch

A small watch carried in a pocket. It appeared around the 17th century when pockets began to be added to men's clothing, and was widely used until it was replaced by wristwatches after World War I. During these 250 years or so, pocket watches made great advances in structure and time accuracy, in the social context of the time when accurate timepieces were required for navigation, observation, and other purposes. For example, the pocket watch with a movement diameter of 63 mm completed in 1802 by Abraham Louis Breguet (1724-1823) of France - named "Marie Antoinette" in memory of the queen who ordered it and was executed by the guillotine in 1793 before it was completed - can be said to be a culmination of the technology of the time. All parts of this watch that did not require steel were made of gold, it was self-winding with platinum weights, had two spring barrels, a mechanism to indicate the winding status, a perpetual calendar that did not require leap year adjustment, a thermometer, an equation of time, three center hands, a stopwatch, and even a striking device that would audibly tell the hour and minute at any time.

Along with efforts to improve escapements and regulators and eliminate temperature errors, GE Roskopf (1813-1889), a German who had settled in Switzerland in 1867, attempted to popularize clocks, which had previously been the property of a select few, for the masses. This clock was completely devoid of decorative elements, extremely simplified in structure, and proactively adopted the pin-lever escapement and crown system instead of key winding of the mainspring, both new inventions at the time, and was sold at about one-quarter the price of regular watches. Pocket watches disappeared from the market after World War II, but watches with pin-lever escapements are still called "Roskopfs" to this day.

[Kuniyuki Motomochi]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

洋服のポケットなどに入れて持ち歩く小型の時計。17世紀ごろ、男性の衣服にポケットがつくようになるとともに現れ、第一次世界大戦後、腕時計にその地位を譲るまで広く用いられた。この約250年の間に、懐中時計は航海や観測などのため正確な時計を求める当時の社会的な背景のもとで、構造、時間精度のうえで大きな進歩を遂げた。たとえばフランスのブレゲーAbraham Louis Breguet（1724―1823）が1802年に完成した機械部の直径63ミリメートルの時計――その完成を待たず1793年に断頭台に消えた注文者の王妃をしのんで「マリ・アントアネットMarie Antoinette」と名づけられた懐中時計――は、当時の技術を集成したものといえる。この時計は、鋼を必要としない部分はすべて金、自動巻きでおもりは白金、ぜんまい香箱二つを備え、巻き状態を指示し、閏年(うるうどし)調整不要の永久カレンダー、温度計、均時差、中三針、ストップウォッチ、そしていつでも何時何分までを音で知らせる引打ち装置までも備えていた。

　脱進機、調速機の改良、温度誤差排除への努力と並んで、限られた階級の所有物であった時計を大衆に普及させようという試みが、1867年スイスに定住していたドイツ人のロスコフG. E. Roskopf（1813―1889）によって行われている。この時計は装飾的要素をいっさい省き、構造を極度に簡素化し、当時の新しい考案であるピンレバー脱進機とぜんまいの鍵(かぎ)巻きにかわる竜頭(りゅうず)方式を進んで採用し、普通品の約4分の1の価格で売り出された。懐中時計は第二次世界大戦後、市場から姿を消したが、ピンレバー脱進機をもつウォッチはいまなお「ロスコフ」とよばれている。

［元持邦之］

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