In 1893 he invented the Karussel movement for watches, which allowed timepieces to be handled more roughly or kept horizontal while keeping good time. His efforts were rewarded with excellent performance in the trials of pocket and deck watches at the Royal Observatory, Greenwich, in which the majority of top-performing watches were soon fitted with the Karussel. Precision in timekeeping was an essential part of nautical astronomy at the time, and the only reliable method of navigation at sea.
Bonniksen also maintained an interest in astronomy and was elected a member of the Royal Astronomical Society in 1905. In 1906 he posted an advertisement in the Observatory magazine for astronomers, advertising his watchmaking prowess and ability to make specialist equipment including sidereal timekeepers (clocks which follow the movement of the skies which varies over the year relative to Greenwich Mean Time). Later in his career, he turned his attention to the rapidly developing vehicle industry, designing an innovative speedometer mechanism for motor cycles.
Obituaries appeared in both the Monthly Notices of the Royal Astronomical Society and in the Horological Journal in 1936, after his death in Leamington Spa, Warwickshire. His life and work is now commemorated by a wall plaque outside his workshop house in Norfolk Street, Coventry.
Article on wall plaque, Keith Draper, Coventry Evening Telegraph, 2 Dec 2000
Obituary, Monthly Notices of the Royal Astronomical Society, 96, 289 (1936)
Advertisement, The Observatory magazine, 29, 431 (1906)
"The Karussel Watch, by its Inventor", advertising pamphlet, Coventry Archives, PA1462/159/1