In order to know the true situation of a Planet at any particular time, the small set of balls are to be put each on its respective axis; then the winch to be turned round until each index points to the given time.

Rittenhouse was the perfect person to study the mysterious planet as he had a personal observatory on his family farm. In 1763 Mason and Dixon began a survey of the Pennsylvania-Maryland border but this work was interrupted in 1767. Hannah survived David by more than three years dying in late 1799.

David Rittenhouse (April 8 1732 – June 26 1796) was a renowned American astronomer inventor clockmaker mathematician surveyor scientific instrument craftsman and public official.