11. The most common true time source is a GPS master clock . 12. The second hand is driven by an electrical motor independent of the master clock . 13. An electric master clock synchronizing all individual clocks in the building was also installed. 14. Other organs seem to have their own clocks that supplement the brain's master clock . 15. The glitch, which was corrected, affected only the Web site, not the master clock . 16. Besides, there is no good evidence of feedback from the periphery to the master clock . 17. A : To reach the U . S . Naval Observatory master clock , call 202-653-1800. 18. The competition for selling exact time necessitated developing a reliable master clock and auxiliary clocks. 19. ANT's adaptive isochronous scheme doesn't require a master clock . 20. The Synchronome company manufactured electrically operated master clocks , patented in 1907, such as the Shortt-Synchronome clock.
