The Astronomical Observatories of Jai Singh c15.s1.t6.17

c15.s1.t6.17

¹ See the Siddhānta Siromani xi 50-51. The instrument appears to be a perpetual motion machine, which consists of a wheel with hollow (tangential) spokes which are filled with mercury. "The wheel thus filled will, when placed on an axis supported by two posts, revolve of itself." This is an old friend.