Two more things -

First, "hanging rock" could be a double-pun of course because it also refers to Stonehenge (and Newton WAS very interested in Stonehenge, though he never visited it).

Second, although I described the mechanism Stukeley drew as naff, because the support to the levers was so flimsy, the idea of suspending the stone from the levers rather than putting the levers under the stone is pretty clever and arguably has big advantages over what the stonehengineers have been doing - if only a solution could be found to how to provide a decent fulcrum.

IMO the Stonehengineers should make one of their next projects a demonstration of (speculative) Newtonian stone rowing.