 After having designed plans in 1754, he constructed his first chronometers by 1756, and accomplished his masterpiece in 1766.This remarkable chronometer incorporated a detached escapement, a temperature-compensated balance and an isochronous balance spring, innovations which would be adopted in subsequent chronometers.Harrison demonstrated a reliable chronometer at sea, but these developments by Le Roy are considered by Rupert Gould to be the foundation of the modern chronometer.