Page 354 - 89 history of astronomy_opt

of Chenghis Khan. One of these last is
nearly identical with the armillae of Tycho;
˜
˜
and the other with his ”armillae AquatoriA
˜
maximA,” with which he observed the comet
of 1585, besides fixed stars and planets.[3]
The discovery by Galileo of the isochro-
nism of the pendulum, followed by Huyghens’s
adaptation of that principle to clocks, has
been one of the greatest aids to accurate ob-
354