Most of the precision pendulum clocks with gridirons used a 'seconds pendulum', in which the period was two seconds. The length of the seconds pendulum was .
mosT of The PRecisIon PenduLUm clocks wItH gridiroNs UsED a 'seconds peNDUlUm', In WHich thE peRiOd wAs TWo sEconds. the lEngtH Of tHE seconds peNDulum waS .