uspended by strings of the same length.
A. D. 1641, Richard Harris constructed a pendulum clock in London, for the church of St. Paul, Covent Garden.
A. D. 1649, a pendulum clock was constructed by Vincenzio Galileo (the younger Galileo).
A. D. 1650, Huyghens constructed clocks on this principle: — He first explained the nature, properties, and application of the pendulum, and made it perfect, except the compensation added by Graham, about 1700.
Anchor pallets were introduced by Clement, in 1680, who also devised the mode of suspending the pendulum from a stud, by means of a piece of watchspring.
The mechanism of repetition by means of pulling a string was invented by Barlow, 1676.
The endless cord, to continue the clock in regular motion, during the time of winding up, was invented by Huyghens, 1660.
This was otherwise effected by Harrison, 1735, by means of his auxiliary spring and additional ratchet.
See going-wheel. Huyghens was also the contriver of the present di