In 1913, Blériot Remembers ZENITH’s precision with these terms that he shared while in the manufacturer’s guestbook: “I am very pleased with the ZENITH view which I ordinarily use And that i are unable to endorse it really adequate to individuals who care about precision”. 6 miles, or 55.7 km) https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/