 He proceeded to redesign the concept of the watch as a timekeeping device, basing his design on sound scientific principles.He had already in the early 1750s designed a precision watch for his own use, which was made for him by the watchmaker John Jefferys 1752–1753.This watch incorporated a novel frictional rest escapement and was not only the first to have a compensation for temperature variations but also contained the first miniature 'going fusee' of Harrison's design which enabled the watch to continue running whilst being wound.